A boat`s speed in still water is 20 km/h . If the boat is to travel directly across a river whose current has a speed of 12 km/h, at what upstream angle must the boat head ?

a) The stone is 1046 feet above the ground

b) It takes 1 second to return to the ground

c) The speed as it returns to the ground is 259 feet/s.

We know that when an object is thrown up or thrown down, the motion of the object would occur under the influence of gravity and we have to apply the equations of kinematics in each case.

Given that;

a) h = ut - 1/2gt^2

h = height attained

u = initial velocity

g = acceleration due to gravity

t = time taken

h = (16 *2) - 1/2(-32 * (2)^2)

h = 32 + 64

h = 96 feet

The distance above the ground = 96 feet + 950 feet = 1046 feet

b) v = u + gt

Given that v = 0 at the maximum height

0 = 16 + (-32) * t

t = 16/32

t = 0.5 secs

To go up and return;

2(0.5 secs) = 1 second

c) v^2 = u^2 + 2gh

v = √(16)^2 + (2 * 32 * 1046)

v = 259 feet/s

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Answer:

Hello, I'm here to help you.

↬ 78%

Explanation:

↬ Think that about 70% of the area of the earth is covered by the ocean.

↬ So the precipitation that falls on it is a smiliar percentage.

Answer:

A

Explanation:

potential energy is usually at rest at the highest point in comparason to the ground

The gravitational potential energy (PE) of an object is given by the formula:

PE = mgh

where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object above some reference point.

In this case, the bell has a PE of 8,550 J and a mass of 20 kg. We can rearrange the above formula to solve for the height h:

h = PE/(mg)

Substituting the given values, we get:

h = 8,550 J / (20 kg x 9.81 m/s^2) ≈ 43.4 meters

This is the height from which the bell falls. When the bell falls to the ground, all of its PE is converted to kinetic energy (KE). The formula for KE is:

KE = (1/2)mv^2

where m is the mass of the object and v is its velocity.

Setting the PE equal to the KE, we get:

PE = KE

mgh = (1/2)mv^2

Simplifying and solving for v, we get:

v = √(2gh)

Substituting the values for g and h, we get:

v = √(2 x 9.81 m/s^2 x 43.4 m) ≈ 29.4 m/s

Therefore, the final velocity of the bell when it hits the ground is approximately 29.4 m/s.

a).  frequency = (speed) / (wavelength)

The speed of light is around 3 x 10⁸ m/s.

For 380 nm (violet light), frequency = (3 x 10⁸ m/s) / (380 x 10⁻⁹ m)

Frequency = 7.89 x 10¹⁴ Hz

For 760 nm (red light), frequency = (3 x 10⁸ m/s) / (760 x 10⁻⁹/s)

Frequency = 3.94 x 10¹⁴ Hz

The ratio is 2 .

That's 1 octave, or 0.3 of a decade.

b).  The ratio of highest/lowest sounds is (20,000 Hz/20 Hz) = 1,000

That's 3 decades, or about 10 octaves.

===> Speaking logarithmically ( ! ), ears are sensitive to a range of sound frequencies that's 10 times as wide as the range of light frequencies that eyes can detect.

Answer:

Explanation:

Remark

Let's start with the second question first. If the two forces aren't balanced, the truck will move in some direction. So the downward force of the truck must equal the upward force provided by the pavement pushing up.

Mass of truck = 9500 kg. Remember mass is directionless and it is not a force or weight. That truck would have a mass of 9500 kg anywhere in the universe.

Givens

m = 9500

a = 9.8

Force or weight = ?

Formula and Solution

F = m * a

F = 9500 * 9.8

F = 93100 N

Comment

That force does have a direction. It is down.

The balancing force (you call it the reaction force) going upward is 93100 N

Determining the volumes of solid samples by measuring their dimensions and calculating it mathematically may be less accurate than determining their volumes by water displacement. Yes, the water displacement method can work for calculating the density of a tablespoon of sugar.

This is because the dimensions of the objects may not be perfectly uniform and there may be small irregularities that could lead to inaccuracies in the calculated volume. Water displacement, on the other hand, provides a more accurate measure of the volume of irregularly shaped objects.

This method involves measuring the volume of water displaced by the sugar when it is added to a graduated cylinder of water. The difference between the initial and final water levels gives the volume of the sugar. The mass of the sugar can then be measured using a scale.

The density can be calculated by dividing the mass of the sugar by its volume. However, it is important to ensure that the sugar is fully dissolved in the water to obtain an accurate measurement.

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The time it takes for the car to fall from a certain height would not be affected by the time it takes for the ball to fall, even if the car's velocity were doubled.

If the car's velocity were doubled, the time it takes for the car to fall would not be affected by the time it takes for the ball to fall. This is because the time taken for an object to fall from a certain height is determined by the acceleration due to gravity and the distance from the ground, but not by the object's initial velocity.

The acceleration due to gravity is constant, which means that the time taken for an object to fall a certain distance is also constant. This means that the time taken for the ball to fall and the car to fall from the same height would be the same, regardless of the car's velocity.

This can be explained by the equation of motion for a falling object:

d = 1/2gt²,

where d is the distance from the ground, g is the acceleration due to gravity, and t is the time taken to fall.

Since the acceleration due to gravity is constant, the time taken for the car and the ball to fall the same distance would be the same, regardless of their initial velocity.

Therefore, if the car's velocity were doubled, the time it takes for the car to fall would be the same as before, but it would be moving faster when it hits the ground.

In conclusion, the time it takes for the car to fall from a certain height would not be affected by the time it takes for the ball to fall, even if the car's velocity were doubled.

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Answer:

50 km/h

Explanation:

100km/2hours = 50 km/h

Answer:

All of the above is the correct answer!!!

Explanation:

mark me brainliest

The frequency of the pendulum is 0.397 Hz, which means that the pendulum completes 0.397 cycles per second. This value can also be expressed as 23 cycles per 58 seconds or 46 cycles per 116 seconds, etc.

The frequency of a wave or oscillation is defined as the number of cycles completed per unit time. In this case, we are given that a pendulum completes 23 full cycles in 58 seconds. Therefore, the frequency of the pendulum can be calculated by dividing the number of cycles by the time taken.

Frequency = Number of cycles / Time

Substituting the given values, we get:

Frequency = 23 / 58

Frequency = 0.397 Hz

Therefore, the frequency of the pendulum is 0.397 Hz, which means that the pendulum completes 0.397 cycles per second. This value can also be expressed as 23 cycles per 58 seconds or 46 cycles per 116 seconds, etc.

The period of the pendulum can be calculated by taking the reciprocal of the frequency, i.e., the time taken for one complete cycle. In this case, the period is 2.52 seconds (1 / 0.397), which means that it takes the pendulum 2.52 seconds to complete one full swing.

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Answer:

15009

Explanation:

PE = mgh

PE = 61.2(9.81)(10 * 2.50)

PE = 15009.3

The spring constant is 2.5 ft-lb/ft.

Spring constant is a physical constant associated with a spring in a mechanical system. It is a measure of the stiffness of the spring, and is equal to the ratio of the force applied to the spring to the resulting displacement of the spring. The spring constant is usually denoted by the letter k. The unit of the spring constant is newtons per meter (N/m). In a linear system, the spring constant is a constant, and does not depend on the magnitude of the force applied or the displacement of the spring. The spring constant of a system is determined by the material properties of the spring and its geometry.

The spring constant, or stiffness, of a spring is defined as the amount of force (in units of force, such as pounds or Newtons) required to stretch the spring a certain amount (in units of distance, such as feet or meters).

Spring Constant = Work / Distance = 10 ft-lb / 4 ft = 2.5 ft-lb/ft.

Therefore, the spring constant is 2.5 ft-lb/ft.

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The rate of heat that must be supplied to the engine for it to produce 5 hp of power is 7635 btu/h.

The formula for the efficiency of a completely reversible heat engine:

Efficiency = 1 - (Tc/Th)

where Tc is the temperature of the cold sink and Th is the temperature of the hot source. Since the engine is completely reversible, it operates at the maximum possible efficiency, which means:

Efficiency = 1 - (Temperature_sink / Temperature_source)
Efficiency = 1 - (500/1500) = 2/3

We also know that power (P) is related to the rate of heat transfer (Q) by the formula:

P = Q x efficiency

We can rearrange this formula to solve for Q:

Q = P / efficiency

Plugging in the given values, we get:

Q = (5 hp x 2545 btu/hp) / (2/3) = 7635 btu/h

Therefore, the heat must be supplied to the engine at a rate of approximately 19080.69 BTU/h for it to produce 5 hp of power.

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The force between two charges can be found by using Coulomb's law. Coulomb's law states that the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. This law can be represented by the equation: F = kq1q2 / r² whereF is the force k is the Coulomb constant q1 and q2 are the magnitudes of the two charges and r is the distance between the two charges.In the given question, q1 = -2.0 x 10^-4 C (negative charge) and q2 = 6.2 x 10^-4 C (positive charge). The distance between them is r = 0.22 m. Substituting these values into the equation:F = kq1q2 / r²

We get:F = (9 x 10^9 Nm²/C²) x (-2.0 x 10^-4 C) x (6.2 x 10^-4 C) / (0.22 m)²Simplifying,F = -0.157 N

Thus, the force between the two charges is -0.157 N (attractive force).

Force : An influence that alters the velocity, or acceleration, of a mass-moving object is known as a force. It is a vector quantity because it can be either a push or a pull, always with magnitude and direction.

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A Van De Graaf generator is an electrostatic generator and may collect a large enough charge to produce an electric current. Option A.

A Van de Graaff generator is an electrostatic generator that uses a moving belt to store charge in hollow metal spheres on insulating posts, producing very high potentials. Produces direct current (DC) at low currents and very high voltages.

Van de Graaff generator the motor turns silicone rollers to move rubber bands. As the belt moves, electrons are transferred from the rubber belt to the silicone roller charging the belt positively and the roller negatively. Van de Graaff generators extract electrons from the Earth move them along belts and store them in large spheres. These electrons repel each other and try to separate as much as possible by spreading over the surface of the sphere.

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Answer:

solution

Explanation:

Answer:

When a substance dissolves in water, you can’t see it anymore, it’s still there, but has mixed with the water to make a transparent liquid called a solution. The bonds in salt compounds are called ionic because they both have an electrical charge—the chloride ion is negatively charged and the sodium ion is positively charged.

Explanation:

With an object having a mass of 26.94 grams and a volume of 2.568 cubic centimeters, the object is likely to be made of aluminum.

Aluminum is the likely material for the object with a mass of 26.94 grams and a volume of 2.568 cubic centimeters. This conclusion is based on the fact that aluminum has a relatively low density, making it a plausible candidate for an object with these specifications.

Density is defined as mass per unit volume. By dividing the mass (26.94 grams) by the volume (2.568 cubic centimeters), we can calculate the density of the object. The density of aluminum is approximately 2.7 grams per cubic centimeter. Comparing this with the given density value, it becomes apparent that the calculated density is close to the known density of aluminum.

Therefore, it is reasonable to conclude that the object is made of aluminum.

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Answer:

1)  10 kg-m/s

2)  2 kg

3)  20 m/s

Explanation:

The momentum of an object can be calculated using the equation:

\(\large\boxed{p=mv}\)

where:

\(\hrulefill\)

For this question we need to find the momentum of a bowling ball whose mass is 4.0 kg is rolling at a rate of 2.5 m/s.

Given values:

Substitute the given values into the momentum formula and solve for p:

\(p=4.0\;\text{kg} \cdot 2.5\;\text{m/s}\)

\(p=10\;\text{kg m/s}\)

Therefore, the momentum of the bowling ball is 10 kg-m/s.

\(\hrulefill\)

For this question we need to find the mass of a skateboard rolling at a velocity of 3.0 m/s with a momentum of 6.0 kg-m/s.

Given values:

As we want to find mass, rearrange the momentum formula to isolate m:

\(\large\boxed{m=\dfrac{p}{v}}\)

Substitute the given values into the formula and solve for m:

\(m=\dfrac{6.0\; \text{kg m/s}}{3.0\; \text{m/s}}\)

\(m=2\;\text{kg}\)

Therefore, the mass of the skateboard is 2 kg.

\(\hrulefill\)

For this question we need to find the velocity of a baseball with a mass of 0.5 kg and a momentum of 10 kg-m/s.

Given values:

As we want to find velocity, rearrange the momentum formula to isolate v:

\(\large\boxed{v=\dfrac{p}{m}}\)

Substitute the given values into the formula and solve for v:

\(v=\dfrac{10\; \text{kg m/s}}{0.5\; \text{kg}}\)

\(v=20\;\text{m/s}\)

Therefore, the velocity of the baseball is 20 m/s.

Answer:

u look at em .<.

Explanation:

lol sorry im just bored

The true statements are:Jupiter's Great Red Spot is in the southern hemisphere.The fastest wind speed recorded in our solar system is on Neptune.

Among the given statements, only two are true. Jupiter's Great Red Spot, a massive storm, is indeed located in the southern hemisphere of the planet. The Great Red Spot is a prominent feature on Jupiter, visible as a giant swirling storm system. On the other hand, the fastest wind speed recorded in our solar system, reaching speeds of up to 2,100 kilometers per hour (1,300 miles per hour), is found on Neptune.

The strong winds on Neptune contribute to its dynamic atmosphere and the formation of features like the Great Dark Spot. The remaining statements about Pluto, Saturn's moon Enceladus, and Uranus are not true according to our current understanding.

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Answer:

60

Explanation:

(hint: speed = distance/time)

The average speed for this trip will be \(\rm 60 mile\ hr^{-1}\). The ratio of the total distance and time is average velocity.

The total distance traveled by an object divided by the total time taken is the average speed.

The average speed of an object indicates the pace at which it will traverse a distance. The metric unit of speed is the meter per second.

The given data in the problem is;

t is the time taken = 5 hour

d is the distance tyravelled=300 miles

The average velocity is found as;

\(\rm v_{avg} = \frac{d_{total}}{t{total}} \\\\\ \rm v_{avg} = \frac{300}{5} \\\\ \rm v_{avg} = 60 mile\ hr^{-1}\)

Hence the average speed for this trip will be \(\rm 60 mile\ hr^{-1}\)

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Spectral features that allow the differentiation of the product from the starting material can be identified using various techniques such as infrared spectroscopy and nuclear magnetic resonance spectroscopy.

The chemical structure of a substance determines its spectral features, making it possible to differentiate it from other substances. Spectroscopic techniques like nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy can be used to identify different types of molecular bonds, enabling the differentiation of different types of chemicals.NMR spectroscopy enables the determination of the types of atoms in a substance by analyzing the radiation emitted by the nucleus of the atom. On the other hand, IR spectroscopy identifies the types of chemical bonds in a substance by analyzing the infrared radiation absorbed by the sample.

Spectral features that differentiate the product from the starting material can be identified using various techniques such as infrared spectroscopy and nuclear magnetic resonance spectroscopy. NMR spectroscopy can determine the types of atoms in a substance by analyzing the radiation emitted by the nucleus of the atom, while IR spectroscopy can identify the types of chemical bonds in a substance by analyzing the infrared radiation absorbed by the sample. The chemical structure of a substance determines its spectral features, enabling its differentiation from other substances.

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Speed is rate of change of distance with respect to time and Acceleration is rate of change of velocity with respect to time.

Speed is  "rate of change of Distance with respect to time".

i.e. v= dx/dt it is also defined as Distance over time.

i.e. v=Displacement/Time.

Speed shows how much distance can be covered in unit time. It's SI unit m/s.  dimension of Speed  is [L¹T⁻¹]

Acceleration is "rate of change of velocity with respect to time".

i.e. a = dv/dt

if an object changes its velocity in short time, we can say that it has grater acceleration. a= dv/dt =Δv/Δt . Its Si unit is m/s².

Dimension of acceleration is [L¹ T⁻²]

Hence this is difference between speed and acceleration.

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Answer:That only applies to highly polished surfaces, eg mirrors.

If you take a high quality laser (ie with low divergence) and aim it at a wall, you can see the spot where the laser beam reaches the wall from anywhere with a direct line-of-sight to the spot where the laser beam reaches the wall. This due to micro imperfections on the surface of the wall. At a microscopic level, the wall surface is very rough and pointing in all directions.

As to why, a beam of light bounces of a highly polished surface, I can only surmise that it is essentially due to kinematics, ie the only force opposing the light beam is normal to the surface, hence there no forces along the reflective surface. Since there are no forces along the reflective surface, the speed component of light along the reflective surface remains unchanged. However, on the plane perpendicular to the reflective surface the, the light photons bounce off at the same speed at which the hit the reflective surface because the mass of the reflective surface is much much much larger than the mass of the photons, which means that the reflective surface won’t move at all. Since conservation of momentum requires that momentum after the collision be the same as the momentum before the collision then the only way for that to happen is if the velocity of the photon perpendicular to the reflective surface is of exactly the same magnitude but in the opposite direction. Vector resolution of the speed component of the reflected beam means that the angle of reflection must be the same as the angle of incidence.

Explanation:

The  value in terms of 1m of oil is 1.25

To convert the pressure at a point from 1 meter of water to its equivalent value in meters of oil, we can use the following formula:

Pressure = height × density × gravity

Let's first find the pressure exerted by 1 meter of water.

1 g x 0.8 = 0,8

1 x g x 1m = 0.8 x g * h2

We are to solve for h2

h2 = 1 / 0.8

= 1.25

Hence tghe  value in terms of 1m of oil is 1.25

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You are able to perceive it as a single strand because of the principle of : Good continuation

Principle of Good continuation states that objects with very smooth edges are easily seen as been continuous ( i.e as a single strand ) rather than objects or materials with rough edges.

The rope coiled on a beach has very smooth edges therefore can be seen as a continuous strand and this is possible due to the principle of good continuation.

Hence we can conclude that You are able to perceive it as a single strand because of the principle of : Good continuation.

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