BVG8Science - Nevis' work & energy examples

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Work and Energy Practice Questions/ Answers :

Example	Is Work Done	Explanation
1. A lever lifts a box to a vertical height of 10 m.	YES	The level is lifting the mass through a vertical distance in the same direction as the force that it applies.
2. A crane is holding a 200kg steel beam over the building.	NO	The crane is motionless.
3. A ball rolls down a hill.	YES	Gravity is pulling the kitten down the hill

Example	Type of Energy Change	Work Completed by....
1. A paintball is shot from a paintball gun.	Potential to Kinetic Energy	The paintball gun.
2. A hitter completes a home run! YAY! and slides to his last base.	Kinetic to Thermal Energy	Friction.
3. A person brings out the garbage and then turns around to go back into their house.	Kinetic to Potential Energy	The body.

Example	Force (N)	Work (J)
1. A 2kg chocolate is lifted from the suitcase to a table 1m away from the floor.	F=mg F=19.6N	w=Fd w=19.6J
2. A crane is lifts a 200kg steel beam over the building that is 44m high.	F=mg F=1,960N	w=Fd w= 86,240J
3. Ms.Keyworth lifts her 20lbs cat and puts her cat into the cage 1m above the floor.	F=mg F=19.6N	w=Fd w= 29.4J