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3 years ago

Which statement about gravity is true? L

Physics

1 answer:

stealth61 [152]3 years ago

7 0

Answer:

The last statement.

Explanation:

Gravity is mgh where m is the mass of the object or the person, g is the gravitational field strength acting on it and h is the height of alleviation of the object or the person and thus is not affected by other forces.

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What is power?

e-lub [12.9K]

Answer:

B) Power is the rate at which work is done

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3 years ago

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A bicycle consists of which types of simple machines? Check all that apply. lever

OleMash [197]

<span>A bike is compound machine.This means that it is made up of a bunch of different simple machines. Screws are used to hold the pieces together. The wheel of a bicycle is a wheel and axle. The pedals are also examples of this simple machine. The pedals are attached to a lever that turns a pulley.</span>

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3 years ago

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Consider the same roller coaster. It starts at a height of 40.0 m but once released, it can only reach a height of 25.0 m above

poizon [28]

Answer:

The magnitude of the frictional force between the car and the track is 367.763 N.

Explanation:

The roller coster has an initial gravitational potential energy, which is partially dissipated by friction and final gravitational potential energy is less. According to the Principle of Energy Conservation and Work-Energy Theorem, the motion of roller coster is represented by the following expression:

$U_{g,1} = U_{g,2} + W_{dis}$

Where:

$U_{g,1}$ , $U_{g,2}$ - Initial and final gravitational potential energy, measured in joules.

$W_{dis}$ - Dissipated work due to friction, measured in joules.

Gravitational potential energy is described by the following formula:

$U = m \cdot g \cdot y$

Where:

$m$ - Mass, measured in kilograms.

$g$ - Gravitational constant, measured in meters per square second.

$y$ - Height with respect to reference point, measured in meters.

In addition, dissipated work due to friction is:

$W_{dis} = f \cdot \Delta s$

Where:

$f$ - Friction force, measured in newtons.

$\Delta s$ - Travelled distance, measured in meters.

Now, the energy equation is expanded and frictional force is cleared:

$m \cdot g \cdot (y_{1} - y_{2}) = f\cdot \Delta s$

$f = \frac{m \cdot g \cdot (y_{1}-y_{2})}{\Delta s}$

If $m = 1000\,kg$ , $g = 9.807\,\frac{m}{s^{2}}$ , $y_{1} = 40\,m$ , $y_{2} = 25\,m$ and $\Delta s = 400\,m$ , then:

$f = \frac{(1000\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (40\,m-25\,m)}{400\,m}$

$f = 367.763\,N$

The magnitude of the frictional force between the car and the track is 367.763 N.

7 0

3 years ago

Suppose a piano tuner hears 2 beats per second when listening to the combined sound from her tuning fork and the piano note bein

maksim [4K]

Answer:

further tightening is required.

Explanation:

The beat created / sec = difference of frequencies

Initial beat heard = 2

so difference of frequencies = 2

after tightening beat heard = 1

difference of frequencies decreases because frequency of tuning fork was higher than piano sound.

on further tightening difference decreases because tightening increases the frequency of piano hence further tightening is required for resonance.

6 0

3 years ago

Two force of 126N and 215N act on an object,calculate the magnitude and direction

yan [13]

The magnitude of the net force could be anything from 89N to 341N , and it could be acting in ANY direction.

To solve both mysteries we need to know the directions of the original two forces.

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3 years ago