mabel and maude are seesawing on the school playground and decide to see if they can move to the correct location to make the seesaw balance. mabel weighs 449 n n and she sits 3 m m from the fulcrum of the seesaw. where should 555 n n maude sit to balance the seesaw?
Answers
Maude is sit about 2.42 meters from the fulcrum to balance the seesaw.
To balance the seesaw, the torques on both sides of the fulcrum should be equal. The torque is calculated by multiplying the weight of the person by the distance from the fulcrum:
torque = weight x distance
Let x be the distance from the fulcrum to Maude's position. Then the torque on Mabel's side is:
torqueMabel = 449 N x 3 m = 1347 Nm
To balance the seesaw, the torque on Maude's side should be equal to 1347 Nm:
torqueMaude = 555 N x x m = 1347 Nm
Solving for x, we get:
x = torqueMaude / weightMaude = 1347 Nm / 555 N ≈ 2.42 m
Therefore, Maude should sit about 2.42 meters from the fulcrum to balance the seesaw.
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Related Questions
in ideal projectile motion, the velocity and acceleration of the projectile at its maximum height are, respectively
A. horizontan, vertical downward.
B. zero, horizontal.
C. zero, vertical downward.
D. horizontal, zero.
E. zero, zero.
Answers
"In ideal projectile motion, the velocity and acceleration of the projectile at its maximum height are horizontal and vertical downward respectively." Correct option is A.
When a projectile is at its highest point, it only has a horizontal component of velocity, hence the vertical component of its velocity is zero.
In projectile motion, the substance or body is launched into the air and only experiences a vertical downward acceleration (g) at each time. The projectile will therefore experience an acceleration of 9.80 m/s² in a vertical downward direction at its highest point.
The projectile will reach its highest point when it reaches a vertical velocity of zero, at which point gravity will start to propel it downward. The projectile's range, which is determined by the object's initial velocity, is its horizontal displacement.
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Tarzan swings back and forth on a
vine with a period of 7.27 s. How
long is the vine?
(Unit = m)
Answers
Answer:
Considering Tarzan as a point mass at point L and using the equation for a simple pendulum:
P = 2 pi (L / g)1/2
P^2 = 4 pi^2 L / g
L = g P^2 / (4 pi^2) = 9.8 m/s^2 * 7.27^2 s^2 / (4 pi^2) = 13.1 m
Answer: 13.1
Explanation:
give two disadvantage of hydroelectric power
Answers
Explanation:
damming of water which changes water flow, in turn could/does cause road/ property flooding
directly being related to water usage, if we have droughts(lack of rain) there we have less water to use for the power.
Environmental consequences
Limited Reservoirs
Sound energy travels through matter in waves. Do sound waves travel
faster through air or water? Explain your answer.
Answers
Answer:
So I think that the sound waves travel faster through water than air.
Explanation:
And the explanation would be that sound travels faster in more denser substances like water.
What is the relationship between distance and sound wave return time?
Answers
What is the answers of this ! Need help I don’t know what to do
Answers
Answer:
1) Mass of Egg Chamber → 35 g = 35 g × 1 kg/(1000 g) = 0.035 kg
2) Average Mass of Grade A Egg → 56.7 g = 0.056 kg
3) Calculated Mass
Drop Chamber + Egg → (35 + 56.7) g = 91.7 g = 91.7 g × 1 kg/(1000 g) = 0.0917 kg
4) Time of Drop → 1.5 seconds
5) Maximum Velocity of Drop Chamber (v = g·t) → v = 9.8 m/s² × 1.5 s = 14.7 m/s
6) Maximum Momentum of Drop Chamber
(P = m·v) (right before hitting the ground) → p = 0.0917 kg × 14.7 m/s = 1.34799 kg·m/s
7) Final End Momentum of Drop Chamber → After landing, velocity v = 0 m/s
(p = m·v after landing) \({}\) ∴ p = m·v = m × 0 m/s = 0 kg·m/s
8) Impulse on Impact → \({}\) (0 - 1.34799) kg·m/s = 1.34799 kg·m/s
(Δm·v = Final - Initial)
9) Force on Impact \({}\) → F·t = Δm·v = 1.34799 N·s
(F·t = Δm·v)
Explanation:
Amy and ellie left school at the same time, but she and ellie arrived at their homes at the same time. compare the girls speeds. use evidence of the distance each girl travels at the time it takes to travel that distance to support your claim. explain your reasoning.
Answers
this is confusind so plzzz help me
Answers
A bullet travelling horizontally with speed of 30m/s strike a wooden plank normal it surface, passing through it with a speed of 10m/s. Find the time taken by the the bullet to pass through the wooden plank of 5cm thickness
Answers
The bullet takes 0.0025 seconds to pass through the wooden plank of 5 cm thickness when it is traveling horizontally with an initial speed of 30 m/s and a final speed of 10 m/s.
The time taken by the bullet to pass through the wooden plank can be determined using the equation of motion for constant acceleration.
Given:
Initial speed (u) = 30 m/s
Final speed (v) = 10 m/s
Distance (s) = 5 cm = 0.05 m
To find the time taken (t), we need to calculate the acceleration (a) first. We can use the equation:
v² = u² + 2as
Rearranging the equation, we have:
a = (v² - u²) / (2s)
Substituting the given values:
a = (10² - 30²) / (2 * 0.05)
Simplifying the expression:
a = (-800) / (0.1)
a = -8000 m/s²
The negative sign indicates that the acceleration is in the opposite direction of the initial velocity.
Next, we can use the equation of motion:
v = u + at
Substituting the values:
10 = 30 + (-8000) * t
Simplifying the equation:
-8000t = -20
Dividing by -8000:
t = 20 / 8000
t = 0.0025 s
Therefore, the time taken by the bullet to pass through the wooden plank of 5 cm thickness is 0.0025 seconds.
To find the time taken by the bullet to pass through the wooden plank, we need to calculate the acceleration first using the equation of motion.
By rearranging the equation and substituting the given values, we can find the acceleration.
Then, using the equation of motion again, we can solve for time.
The negative sign in the acceleration indicates that it is in the opposite direction of the initial velocity.
The resulting time is 0.0025 seconds.
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How would the model change as the atom forms bonds? The third shell would have eight electrons after the atom gains seven electrons to fill the outermost shell. The third shell would be empty so that the eight electrons in the second level would be outermost after the atom loses one electron. The first and third shells would be empty so that the atom would have eight electrons in its remaining shell after the atom loses three electrons. The first shell would have two electrons and the second shell would have six electrons after the atom loses three electrons.
Answers
Answer:
The third shell would be empty, so the eight electrons on the second level would be the outermost after the atom lost one electron
Explanation:
When an atom is bonded with other atoms, a more stable configuration must be reached, which is why the energy of the molecule is less than the energy of the individual atoms, for this to happen in general, electrons are shared or lost and gained in each atom, depending on the electronegative of the same.
If we analyze an atom within the molecule, its last shell is full, in the case of atoms with few electrons in this shell, they are lost and in the case of many electors in this shell, it gains electrons to have eight (8) in total.
When reviewing the different answers, the correct one is:
* The third shell would be empty, so the eight electrons on the second level would be the outermost after the atom lost one electron
Answer: It’s B
Explanation:
A high-temperature gas is compared to the same gas at lower temperature. Which of the following statements is true?
A. Every molecule in the high-temperature gas is moving faster than every molecule in the low-temperature gas.
B. The average molecular speed in the high-temperature gas is faster than the average molecular speed in the low-
temperature gas.
C. Both A and B are true.
D. Neither A nor B is true.
Answers
Answer:
I think it is C
Explanation:
If the temperature of a gas increases, the gas particles have a higher average speed as they gain kinetic energy. They collide more frequently with the walls of the container, which produces a bigger pressure.
a 73.4kg astronaut floats a distance of 24m from a 62000kg space shuttle. what is the force that the space shuttle exerts on the astronaut?
What is the force the astronaut exerts on the space shuttle?
Answers
The force exerted by the space shuttle on the astronaut is equal in magnitude and opposite in direction to the force exerted by the astronaut on the space shuttle. The force exerted by the astronaut on the space shuttle is zero since there is no acceleration involved.
To determine the force exerted by the space shuttle on the astronaut and vice versa, we can use Newton's third law of motion, which states that every action has an equal and opposite reaction.
Force exerted by the space shuttle on the astronaut:
According to Newton's third law, the force exerted by the space shuttle on the astronaut is equal in magnitude and opposite in direction to the force exerted by the astronaut on the space shuttle.
Therefore, the force exerted by the space shuttle on the astronaut is the same as the force exerted by the astronaut on the space shuttle.
Force exerted by the astronaut on the space shuttle:
The force exerted by the astronaut on the space shuttle can be calculated using Newton's second law of motion, which states that force (F) is equal to mass (m) multiplied by acceleration (a).
In this case, since the astronaut is floating and not accelerating, the acceleration is zero. Therefore, the force exerted by the astronaut on the space shuttle is also zero.
Therefore, the force exerted by the space shuttle on the astronaut is the same magnitude as the force exerted by the astronaut on the space shuttle, but they act in opposite directions.
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A parallel circuit is shown in the diagram above. In this case the current supplied by the battery splits up, and the amount going through each resistor depends on the resistance. If the values of the three resistors are: R1 = 82, R2=82, and R3 = 42, the total resistance is found by: 1/R = 1/8+1/8+ 1/4 = 1/2. This gives R = 22. With a 10 V battery, by V = 1 R the total current in the circuit is: I = V/R = 10/2 = 5 A. The individual currents can also be found using I = V/R. The voltage across each resistor is 10 V, so the resistance across R1 : 2.5A 1.25V 2.5V 1.25A
Answers
Answer:
Huh is there options?
Explanation:
XD I dont understand have a good day tho a better person and smarter person will answer this for u
Federal funding agencies must form committees to decide which telescope projects will receive funds for construction. When deciding whic projects wil be funded, the committees must consider:
that certain wavelengths of light are blocked from reaching Earth's surface by the atmosphere,
how efficiently telescopes work at different wavlengths, and
that telescopes in space are much more expensive to construct than Earth-based telescopes.
Using these three criteria, consider each pairing of telescope proposals listed below. For each pair, state which of the two you would choose to fund and explain your reasoning.
Pair A)
Project Beta: An X-ray wavelength telescope, located near the North Pole, which will be used to examine the Sun.
Project Alpha: An infrared wavelength telescope, placed on a satellite in orbit around Earth, which will be used to view supernovae.
Pair B)
Project Rho: A UV wavelength telescope, placed high atop Mauna Kea in Hawaii at 14,000 ft above sea level, which will be used to look at distant galaxies.
Project Sigma: A visible wavelength telescope, placed on a satellite orbit around Earth, which will be used to observe a pair of binary stars located in the constellation Ursa Major.
Pair C)
Project Zeta: A radio wavelength telescope, placed on the floor of the Mojave Desert, which will be used to detect potential communications from distant civilizations outside our solar system.
Project Epsilon: An infrared wavelength telescope, located in the high-elevation mountains of Chile, which will be used to view newly forming stars (protostars) in the Orion nebula.
Answers
I would choose Project Beta, Sigma, and Epsilon from pair A, pair B, and pair C respectively. These projects would provide valuable insights into solar activity, and binary stars effectively, and are cost-effective.
In pair A) I would fund Project Beta, the X-ray wavelength telescope near the North Pole for examining the Sun. The atmosphere blocks a significant portion of X-ray wavelengths from reaching the Earth's surface, making it crucial to have a telescope situated above the atmosphere. Additionally, studying the Sun at X-ray wavelengths can provide valuable insights into solar activity and phenomena.
On the other hand, Project Alpha, the infrared wavelength telescope on a satellite for viewing supernovae, would face less atmospheric interference as infrared wavelengths can penetrate the Earth's atmosphere to some extent. Moreover, the cost of constructing and maintaining a telescope based on satellite is considerably higher than that of a ground-based telescope.
In pair B) I would choose to fund Project Sigma, the visible wavelength telescope on a satellite for observing a pair of binary stars in Ursa Major. Visible wavelengths are not significantly blocked by the atmosphere, so a ground-based telescope could potentially observe the binary stars effectively.
However, the expense of constructing and operating a satellite-based telescope is considerably higher. Project Rho, the UV wavelength telescope atop Mauna Kea, would face less atmospheric interference for UV observations. Considering the cost factor, it would be more feasible to fund a ground-based telescope.
Pair C) I would choose to fund Project Epsilon, the infrared wavelength telescope in the high-elevation mountains of Chile for viewing newly forming stars in the Orion nebula. The atmosphere is relatively transparent to infrared wavelengths, allowing for ground-based observations. Additionally, the cost of constructing a telescope on the floor of the Mojave Desert for radio wavelength observations might be lower compared to a mountain-based telescope.
Project Zeta's goal of detecting communications from distant civilizations might require more advanced technology and extensive infrastructure, making it a more expensive choice compared to Project Epsilon.
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Question 6 1 pts 6. We often use the "gauge freedom" by F=at (where a = constant). What does this mean? a) we can ignore constant terms in the potential energy b) we can find a Lagrangian where a sele
Answers
In Physics, the gauge freedom is often used by F=at, where a is a constant. Gauge freedom is a gauge symmetry where the theory possesses different configurations with the same physical properties.
Hence, gauge freedom implies that we can use different but equally valid descriptions of the same physical phenomenon or situation.To understand what this statement means, let's break it down into smaller parts:Gauge: In Physics, gauge means different ways of defining a concept that are equal.
For instance, different ways to define the electromagnetic potential vector A that produce the same physical results.Gauge symmetry: It implies that two different gauge choices lead to the same physical results.
For instance, changing the electric potential by a constant does not alter the electric field.
Lagrangian: A Lagrangian is a function that describes a physical system's dynamics.
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What are sport skills sometimes referred to as?
a skill-related fitness
b. performance skills
c. health-related fitness
d. physical fitness
Answers
How can you determine the speed of an object with only a tape measure and a stopwatch?
Answers
We can determine the speed of an object with only a tape measure and a stopwatch first by measuring the distance traveled by any given body and simultaneously measuring the time taken to cover this distance with the help of the stopwatch
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is meter/second. The generally considered unit for speed is a meter per second.
The mathematical expression for speed is given by
speed = total distance /Total time
Suppose a body travels a total distance of 750 meters in a total time of 75 seconds, we can measure this distance with the help of a tape measure and the time with the help of a stopwatch its speed would be 4 meters/seconds
speed = distance measured by tape measure /stopwatch time
= 750/75
= 10 m/s
Thus, we can determine the speed of an object with only a tape measure and a stopwatch
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A force of F= 45 N is used to drag a crate 3 m across a floor.
Answers
ANSWER:
(a) 108 J
(b) 0 J
(c) 108 J
STEP-BY-STEP EXPLANATION:
(a)
Express the relation between horizontal component of work done and force on the crate:
\(W_h=F_h\cdot d\)Here Wh is the horizontal component of the work done on the crate and Fh is the horizontal component of force and d is the distance of the crate across the floor.
Replacing:
\(\begin{gathered} W_h=36\cdot3 \\ W_h=108\text{ J} \end{gathered}\)(b)
Express the relation between vertical component of work done and force on the crate:
\(W_v=F_v\cdot d\)Here Wv is the vertical component of the work done on the crate and Fv is the vertical component of force and d is the distance of the crate across the floor.
Replacing:
\(\begin{gathered} W_h=27\cdot0 \\ W_h=0\text{ J} \end{gathered}\)(c)
Express the relation for total work done by the 45 N force:
\(\begin{gathered} W_{\text{total}}=W_h+W_v \\ \text{ replacing} \\ W_{\text{total}}=108+0 \\ W_{\text{total}}=108\text{ J} \end{gathered}\)how does the formation of a resource affect its distribution?
Answers
Several physical variables, including terrain, climate, and altitude, affect how natural resources are distributed. Resources can be divided into two groups: universal and specific.
The allocation of resources has what purpose?The distribution of resources on earth is referred to by their geographic location or spatial arrangement. Alternatively, the location of the available resources. Every location has the potential to be rich in some resources that people want while being poor in others.
What does a resource in life entail?From a human standpoint, a renewable environment is everything that is taken from the ecosystem to satiate human needs & wants. A resource serves a live organism's demands from a more general biological or ecological standpoint.
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A block with a mass of 5. 0 kg is pushed on a frictionless surface through a distance of 5. 0 m by
applying a horizontal force of 80. 0 N.
Applied
Force = 80. 0 N
m = 5. 0 kg
5. 0 m
If the block starts from rest, what is its final velocity?
Answers
To find the final velocity of the block, you can use the formula for linear momentum:
p = m * v
where p is the momentum, m is the mass of the object, and v is the velocity.
Since the block starts from rest, its initial velocity is zero. The final velocity can be found by rearranging the equation to solve for v:
v = p / m
Plugging in the given values, you get:
v = (80.0 N * 5.0 m) / 5.0 kg = 16.0 m/s
So the final velocity of the block is 16.0 m/s.
If your engine is flooded with gasoline, you should push the accelerator to the floor and hold for:_______.
Answers
You should push the accelerator all the way to the floor and hold for five seconds if your engine is flooded with gasoline.
To find the answer, we need to know about the flooded engine.
What is flooded engine?An engine that is flooded is one that has too much fuel in the vehicle and insufficient airflow.The signs of a flooded engine include difficulty starting the engine, car engine failure after only a few feet, black smoke, and unusual engine noise. We can solve the issue in different ways.In the right manner, push the accelerator or gas pedal all the way to the ground. You must open the car's throttle and let the engine's air flow before depressing the gas pedal.Thus, we can conclude that, You should push the accelerator all the way to the floor and hold for five seconds if your engine is flooded with gasoline.
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Lien is pushing a box across a table. She used a force of 100 N to get the box moving. Which force did she overcome to get the box moving?
a)the downward force of gravity on the box
b)the upward force of the table on the box
c)the reaction force on the box
d)the push force on the box
Answers
A.) The force of gravity acts downward on the box, it plays no role in the horizontal acceleration assuming friction is nonexistent.
B.) The normal force acts upward on the box, it also plays no role in the horizontal acceleration.
C.) The reaction force on the box would be talking about Newton’s 3rd law. The reaction force acts on Lien and not the box. So she herself would have to overcome that reaction force to get the box moving. I believe this is the right answer
D.) The push force would be the force she applied. She wouldn’t have to overcome her own force that correlated with the box. She’d have to overcome the reaction force like I explained in answer C.
We have that from the options, the force require to move the table will be the Reaction force.i.e the force that will get a reaction out of the table i.e is Motion
The reaction force on the box
Correct Option is C
From the question we are told
Lien is pushing a box across a table. She used a force of 100 N to get the box moving
Generally The Force Requird to Move a table is greater than the contiunes force applied to it to en sure it contines in Motion.
Having said that Newtons Third law states for every action there most be an equal and opposite reaction
Therefore
From The options the force require to move the table will be the Reaction for.that is the force that will get a reaction out of the table i.e is Motion
Correct Option is C
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A battery with e.m.f 12v and the internal resistance 0.5ohms is connected to an electric bulb of resistance 2 ohms. Calculate the current
Answers
Answer:
4.8 A
Explanation:
Voltage = current x resistance
(V = IR)
12 = I (0.5 +2)
I = 4.8 A
Part A
Find x-component of v⃗ = (7.5 m/s, 30 ∘ cloockwise from the positive y-axis).
Part B
Find y-component of v⃗ = (7.5 m/s, 30 ∘ cloockwise from the positive y-axis).
Part C
Find x-component of a⃗ = (1.8 m/s2, 30 ∘ above the negative x-axis).
Part D
Find y-component of a⃗ = (1.8 m/s2, 30 ∘ above the negative x-axis).
Part E
Find x-component of F⃗ = (60.0 N, 36.9 ∘ counterclockwise from the positive y-axis).
Part F
Find y-component of F⃗ = (60.0 N, 36.9 ∘ counterclockwise from the positive y-axis).
Answers
The answers for each of the components are x-component of v = 3.75 m/s, y-component of v = 6.496 m/s. x-component of a = 0.9 m/s2y-component of a = 1.56 m/s2x-component of F = 36.0 N, y-component of F= 48.0 N
Part A
The x-component of v can be calculated as shown below:
x-component = v cos θ = 7.5 m/s cos 60º = 7.5 × 1/2 = 3.75 m/s
Part B
The y-component of v can be calculated as shown below:
y-component = v sin θ = 7.5 m/s sin 60º = 7.5 × √3/2 = 6.496 m/s
Part C
The x-component of a can be calculated as shown below:
x-component = a cos θ = 1.8 m/s2 cos 60º = 1.8 × 1/2 = 0.9 m/s2
Part D
The y-component of a can be calculated as shown below:
y-component = a sin θ = 1.8 m/s2 sin 60º = 1.8 × √3/2 = 1.56 m/s2
Part E
The x-component of F can be calculated as shown below:
x-component = F cos θ = 60.0 N cos 53.1º = 60.0 × 0.6 = 36.0 N
Part F
The y-component of F can be calculated as shown below:
y-component = F sin θ = 60.0 N sin 53.1º = 60.0 × 0.8 = 48.0 N
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Using Newton's 2nd law,find the mass if the force is 18 N and the acceleration is 2 m/s/s.
Answers
Answer:
9 kg
Explanation:
According to Newton's second law:
\(f = ma\)
\(m = \frac{f}{a} \)
Given:
f = 18 N
a = 2 m/s^2
Substitute the given values in the formula.
\(m = \frac{18}{2} \)
\(m = 9\)
If you had pulled the box with 300W of power, and did 900J of work, how long did it take to pull the box?
Answers
Answer: 3 seconds
Explanation:
The equation for Power is P=W/tΔ
P= Power(W)
W= Work(J)
t= change in time
So for this equation we have 300=900/t where we need to solve for t which we can do by using algebra
300=900/t
t=900/300
t=3
so t= 3 seconds (s)
What is the final temperature of 0.1 kg of water initially at 22 *C after 10 kj of heat is added
Answers
The final temperature of the given mass of water at the initial temperature is 45.8 ⁰C.
Change in temperature of the waterThe change in temperature of the water is calculated as follows;
Q = mcΔθ
Δθ = Q/mc
where;
c is specific heat capacity = 4200 J/kgCΔθ = (10,000)/(0.1 x 4200)
Δθ = 23.8
Final temperatureT2 - T1 = 23.8
T2 = 23.8 + 22
T2 = 45.8 ⁰C
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Which of the following describes the relationship between work and power
Power is the rate at which work is done.
Power is the total amount of work done
Work is the amount of power that can be captured per second
Work is equal to power over time
Answers
power is the rate at which work is done
The 200-mm test tube also contained some water (besides the metal) that was subsequently added to the calorimeter (in Part A.4.). Considering a higher specific heat for water, will the temperature change in the calorimeter be higher, lower, or unaffected by this technique error?
Answers
Answer:
The temperature change in the calorimeter will be lower
Explanation:
Water is an example of a molecular substance. They have relatively low melting points and boiling points usually below 300° C . Water reacts with metals to a degree varying with their position in the electrochemical series.
The specific heat of water is 4179.6 Joules which is relatively high . This typically implies that water absorbs a larger amount of heat but the increase in temperature of its boiling points is relatively low. Thus; in the 200-mm test tube that contains water and was subsequently added to the calorimeter , the heat present was initially absorbed by the water and that does not result to an increase in the temperature change in the calorimeter. Thus the temperature change in the calorimeter will be lower.
In FIGURE 2, a block of mass m=2.5 kg slides heads on into a spring of spring constant k=320 N/m. When the block stops, it has compressed the spring by 7.5 cm. The coefficient of kinetic friction between block and floor is 0.25. While the block is in contact with the spring and being brought to rest, calculatea. the work done by the spring force.b. the increase in thermal energy of the block-floor system.c. What is the block's speed just as it reaches the spring?
Answers
(a)
The work done by the spring force can be calculated with the formula below:
\(W=\frac{1}{2}kx^2\)Using k = 320 N/m and x = 0.075 m, we have:
\(\begin{gathered} W=\frac{1}{2}\cdot320\cdot0.075^2\\ \\ W=0.9\text{ J} \end{gathered}\)(b)
The increase in thermal energy is given by the work done by the friction force.
To calculate this work, first let's find the friction force:
\(\begin{gathered} F_{friction}=F_{normal}\cdot\mu\\ \\ F_{friction}=m\cdot g\cdot\mu\\ \\ F_{friction}=2.5\cdot9.8\cdot0.25\\ \\ F_{friction}=6.125\text{ N} \end{gathered}\)Now, calculating the work, we have:
\(\begin{gathered} W=F\cdot d\\ \\ W=6.125\cdot0.075\\ \\ W=0.46\text{ J} \end{gathered}\)(c)
The block speed can be found by converting the potential energy from the spring (same value of the calculated work in item a) into kinetic energy for the block:
\(\begin{gathered} PE=KE\\ \\ 0.9=\frac{mv^2}{2}\\ \\ mv^2=1.8\\ \\ 2.5v^2=1.8\\ \\ v^2=\frac{1.8}{2.5}\\ \\ v^2=0.72\\ \\ v=0.8485\text{ m/s} \end{gathered}\)