27. KE and Conservation

27. KE and Conservation

Multiple Choice

If it takes you 1500 J of work to lift a box 1.5 meters above the ground and put it on a shelf, then how much potential energy does it have up there?

• More than 1500 J

• Less than 1500 J

• 1500 J

• Impossible to tell without the mass

Multiple Choice

A bird sits on top of a 639 m tall tower. If its gravitational potential energy up there is 2033 J, what is its mass?

• 3.18 kg

• 31.8 kg

• 0.32 kg

• 13.13 kg

Multiple Choice

A roller coaster has a mass of 250 kg, and is 50 meters above the ground, what is the potential energy?

• 122,625 Joules

• 5,600 Joules

• 234,799 Joules

Multiple Choice

What happens to that potential energy when the coaster goes down?

• It’s lost

• It doesn’t change

• It gets converted into something else

Multiple Choice

A ball rolls down from A, its highest point. At which point(s) does it have the greatest kinetic energy?

• A

• C

• D

• G

Multiple Choice

A ball rolls down from A, its highest point. At which point(s) does it have the greatest potential energy?

• A

• C

• D

• G

Multiple Choice

A ball rolls down from A, its highest point. At which point(s) does it have the least potential energy?

• A

• C

• D

• G

Multiple Choice

Where is PE the greatest (PE_max)?

• 1

• 2

• 3

Multiple Choice

What does that mean for its velocity?

• slowest (v_min)

• fastest (v_max)

Multiple Choice

Where is KE the greatest (KE_max)?

• 1

• 2

• 3

Multiple Choice

What does that mean for its velocity?

• slowest (v_min)

• fastest (v_max)

Multiple Choice

What is the kinetic energy of a 25 kg dog running at a velocity of 5 m/s?

• 312.5 J

• 62.5 J

• 125 J

• 625 J

Multiple Choice

A 2000 kg car has 29,000 J of kinetic energy. How fast is it going?

• 14.5 m/s

• 3.8 m/s

• 29 m/s

• 5.4 m/s