Physics- Forces and Energy

Question 1

Units of energy:

Answer 1

J, kJ, mJ, gJ, tJ

Question 2

Work done by a moving force=

Answer 2

energy transferred

Question 3

units of work are therefore:

Answer 3

Joules

Question 4

The amount of work done (or energy transferred) by a moving force therefore depends on…

Answer 4

the force and the distance moved

Question 5

work done =

Answer 5

force x distance moved

Question 6

When a load is raised vertically, work is being done against the …………… ……….. acting on it.

Answer 6

gravitational force

Question 7

This therefore means that energy is being transferred to the raised load and that it is therefore gaining ………….. ………. ……….. .

Answer 7

gravitational potential energy.

Question 8

Any raised object therefore stores energy in the form of ………. ……… …….

Answer 8

gravitational potential energy

Question 9

equation is: Ep=

Answer 9

m x g x h

Question 10

the kinetic energy of a moving object should increase if:

Answer 10

the mass of the object increases

the velocity of the object increases

Question 11

Ek=

Answer 11

1/2mv^2

Question 12

KE lost by car =

Answer 12

braking force x braking distance

Question 13

A car travelling at twice its previous speed has ……. …… its previous KE

Answer 13

2 times

Question 14

For the same braking force, a car travelling at twice its previous speed will therefore travel …… ……. further during braking.

Answer 14

4 times

Question 15

Braking distances are therefore very dependent on the vehicle’s speed and the braking distance would also be …………. if the speed of the car was greater.

Answer 15

greater

Question 16

When an object is falling its main energy transfer is from gravitational potential energy into kinetic energy. There will also be some transfer into thermal energy due to friction with the air (air resistance). If we assume that friction is negligible then all of the original PE should be transformed to ……. ……

Answer 16

kinetic energy