Show:
Work
Potential and Kinetic Energy
Types of Energies
Conservation of Energy
Random
100

True or False. The definition of work is: A force is applied to an object and the object moves in the opposite direction of the force.

False. To be work, the force and motion must be in the same direction.

100
The ability to do work is called ___________.
energy
100

The energy of moving electrons in wires is called ____________ energy.

electrical

100
What does the law of conservation of energy state?

Energy cannot be created or destroyed

100

The unit work is measured in is...

Joules

200

If a person uses 90N of force to push a box 2m in the direction of their push, how much work was done? (Unit must be correct)

180J

200

Potential Energy PLUS Kinetic Energy is equal to this.

Mechanical energy

200

The movement of atoms and molecules. This is called ______ energy.

thermal

200

Imagine a diver jumping off of a diving board. At what point does the diver have the most potential energy?

While standing on the diving board.

200

The unit energy is measured in is...

Joules
300

How much work is done if someone hold a 4kg book over their head (2m high) for 3 hours?

No work, because there is no motion.

300
Energy on an object due to its motion is called _____________ energy.
kinetic
300

Stored energy in food, gasoline, and other substances is called ______________ energy. Is it kinetic or potential?

chemical; potential

300

Ignoring air resistance, if a rock is falling from a 100m cliff, at what height in the fall is the gravitational potential energy equal to the kinetic energy?

At 50m.

300

The formula for weight is...

mass x acceleration due to gravity

400

Is work a vector or a scalar?

Scalar

400
Stored energy is called _______________ energy.
potential
400

Energy that comes from an atom's nucleus is called ________ energy. 

nuclear

400

When a golf ball is released and bounces on the ground, why does it not then return to the same height it was dropped from?

Energy is lost to sound and heat

400

Why can't a perpetual motion machine work forever?

Eventually, all of the energy will be converted to thermal energy through friction and the machine will stop.

500

A 30kg child is asking his mother to pick him up. She will have to lift him 1m in order to do so. How much work will she have to do in order to pick up her child? (unit must be correct)

30kg x 9.8 m/s/s = 294N x 1m = 294J (estimated 300J is also OK)

500

This is the point in a fall when an object has the most kinetic energy.

Right before it hits the ground.
500

This type of energy occurs when an object vibrates, and this caused the air to vibrate. 

sound

500

If a diver weighs 500N and is standing on a 3m diving board, what will the diver's total mechanical energy be right before they hit the water? (Ignore air resistance) (The unit must be correct)

GPE = 500N x 3m = 1500J (total mechanical energy will be equal to the gravitational potential energy)

500

In what year did Isaac Newton publish his 3 laws of motion? (Plus or minus 5 years)

1687! (if you answered in the range of 1682-1692, it counts)