Work Energy And Momentum

Question 0

How do we calculate work?

Answer 0

Work = force x distance moved in direction of force

Question 1

What do we mean by work done?

Answer 1

The energy transferred when can object is moved.

Question 2

What is kinetic energy?

Answer 2

The energy it has due to motion.

Question 3

How do we calculate kinetic energy?

Answer 3

Kinetic energy = 1/2 x mass x speed^2

Question 4

What type of energy is gravitational potential energy?

Answer 4

Stored energy.

Question 5

What is Elastic potential energy

Answer 5

The energy stored in an elastic object when work is done to the object.

Question 6

How can we tell if an object is elastic?

Answer 6

It returns to its shape after being squashed or stretched.

Question 7

What is momentum?

Answer 7

A property all moving objects possess.

Question 8

How do we calculate momentum?

Answer 8

Momentum = mass x velocity.

Question 9

The most important property of momentum is….

Answer 9

Momentum is conserved whenever two objects interact provided no forces act on them.

Question 10

What is changing momentum called?

Answer 10

Impact force.

Question 11

How do we calculate impact force?

Answer 11

Force = change in momentum / time taken

Question 12

How do we lessen the impact force?

Answer 12

Increase the time for an objects momentum to reach 0.

Question 13

What do air bags do?

Answer 13

Increase the time taken for your head’s momentum to reach 0.

Question 14

Work done to overcome friction is transferred into what?

Answer 14

Mainly heat energy but some sound energy too.

Question 15

How do we calculate GPE?

Answer 15

GPE = mass x gravitational field strength x change in height.

Question 16

When an object moves up does It lose GPE?

Answer 16

No, it gains GPE.

Question 17

When an object falls what is GPE transferred to?

Answer 17

Kinetic energy.

Question 18

Objects prefer to keep moving in the same direction what does this make it difficult to do to objects?

Answer 18

Change the direction of an object with a lot of momentum

Question 19

When two objects push each other apart….

Answer 19

They move apart with equal and opposite momentum.

Question 20

When does a change in momentum occur?

Answer 20

When a force is applaud to the object.

Question 21

Give two ways in which momentum can change?

Answer 21

If the object speeds up or slows down.

Changes direction.

Question 22

The longer the time taken for the change in momentum, the…

Answer 22

Smaller the impact force.

Question 23

When a car crashes what does it do and what does this cause?

Answer 23

Decelerates rapidly causing great forces due to the change in momentum.

Question 24

What force is needed to get a 25 kg stationary bike to move at 12m/s in 5 seconds?

Answer 24

60 Newtons.

Force = change in momentum / time

Question 25

What force is needed to get a 250kg travelling at 40m/s to increase it’s speed to 70m/s in 40 seconds?

Answer 25

Need to work out