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3 years ago

The kinetic energy of a book on a shelf is equal to the work done to lift the book to the shelf. t/f

2 answers:

7 0

The kinetic energy of a book on a shelf is equal to the work done to lift the book to the shelf is false. The kinetic energy on the shelf is zero because it is not in action.

algol [13]3 years ago

6 0

Answer: The given statement is false.

Explanation:

Kinetic energy is defined as the energy obtained by an object because of its motion.

For example, moving a pulley on the road.

Whereas energy of an object obtained due to its position is known as potential energy.

For example, lifting a book from table to the shelf shows position of the book has changed.

Therefore, we can conclude that the statement kinetic energy of a book on a shelf is equal to the work done to lift the book to the shelf, is false.

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What does the solar system consist of?

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Planets, Sun, stars, plasma, and black matter

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3 years ago

Read 2 more answers

If one lawn mower causes an 80-dB sound level at a point nearby, four lawnmowers together would cause a sound level of _________

BartSMP [9]

Answer:

The intensity of 4 lawn movers is 86 dB.

Explanation:

Intensity of one lawnmower = 80 dB

Let the intensity is I.

Use the formula of intensity

$dB = 10 log\left ( \frac{I}{Io} \right )\\\\80=10log\left ( \frac{I}{Io} \right )\\\\10^8 = \frac{I}{10^{-12}}\\\\I = 10^{-4} W/m^2$

Now the intensity of 4 lawn movers is

$dB = 10 log\left ( \frac{4I}{Io} \right )\\\\dB=10log\left ( \frac{4\times10^{-4}}{10^{-12}} \right )\\\\dB = 86 dB\\$

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3 years ago

A ball rolls from rest at the top of a 15.5 m hill, downward to the right and back upward onto a 8.25 m hill. How fast is the ba

lana66690 [7]

Answer:

Explanation:

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3 years ago

Bats use sound to sense objects by sending out short ultrasound pulses and listening for the echo off the object. A. Sketch the

ivann1987 [24]

Answer:

B. t = 0.250s

Explanation:

A. An image with the sketch of the bat emitting a sound, which reflects on a surface and return to the bat is attached below.

B. In order to calculate the time that the pulse emitted by the bat, return to the bat, you first calculate the time that pulse takes to arrive to the object.

You use the following formula:

$x=vt$ (1)

x: distance to the object = 43m

t: time = ?

v: speed of sound beat = 343 m/s

You solve the equation (1) for t:

$t=\frac{x}{v}=\frac{43m}{343m/s}=0.125s$

The time on which the bat hears the echo is twice the value of t, that is:

$t'=2(0.125s)=0.250s$

The time on which bat heart the echo of its sound, from the moment on which bat emitted it, is 0.250s

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3 years ago

a bear has a mass of 500kg and 100,000 J of mechanical kinetic energy. what is the speed of the bear?

3241004551 [841]

Answer: v = 20 m/s

Explanation: Solution:

Use the formula of Kinetic Energy and derive for v:

KE = 1/2 mv²

To find v:

v = √ 2 KE / m

= √ 2 ( 100000 J ) / 500 kg

= √ 400 m/s

= 20 m/s

7 0

4 years ago