Work and Energy

Question 1

When is work done

Answer 1

When a force acts on a body

Question 2

What is work a measure of

Answer 2

Energy transfer

Question 3

Work(J) =

Answer 3

Force(N) * distance(m)

Question 4

What happens to the total energy in a system when work is done

Answer 4

It stays the same, but may change form

Question 5

Kinetic energy(N) =

Answer 5

1/2 * mass(g) * velocity^2(m/s^2)

Question 6

Gravitational potential energy(N) =

Answer 6

Gravitational field strength(kg/N) * deltaHeight(cm)

GFSON EARTH IS 10KG/N

Question 7

Energy in spring(j) =

Answer 7

1/2 * force(N) * extension(cm)
Or
Area under force-extension graph

Question 8

Most important thing about springs

Answer 8

Putting a force on a spring will cause it to extend

Question 9

What does the extension of a spring depend on?

Answer 9

The spring constant (how much force you must put in to stretch it)

Question 10

(Extension of a spring) Force(N) =

Answer 10

Spring constant * extension

Question 11

The efficiency of energy transfer

Answer 11

Inefficient, some energy is lost to friction

Question 12

What are the positives of car efficiency?

Answer 12

Reduce greenhouse gas emissions and energy use

Question 13

How can we make cars more efficient?

Answer 13

Idling, shrinking, streamlining, rolling

Question 14

How does idling make a car more efficient?

Answer 14

Start-stop systems reduce waste when stationary

Question 15

How does shrinking make a car more efficient?

Answer 15

Lighter materials reduce the mass of the car

Question 16

How does streamlining make a car more efficient?

Answer 16

Streamlining the car to reduce work done by frictional forces on the car

Question 17

How does rolling make a car more efficient?

Answer 17

Correctly inflated tyres reduce work done by frictional forces

Question 18

What is a car safety feature?

Answer 18

A feature that reduces forces put upon passengers in a collision

Question 19

What are some car safety features?

Answer 19

Air bags and crumple zones

Question 20

How do crumple zones work?

Answer 20

Change shah during a collision to allow work to be dubs, allowing kinetic energy on passengers to be experienced I think a longer timeframe

Question 21

Why does increasing the timeframe in which kinetic force is felt good

Answer 21

The longer the distance the work is done over, the smaller the force on the passengers will be