# P2: KE and GPE

HideShow resource information
• Created by: ja7sa096
• Created on: 24-04-16 12:56
What are the 9 forms of energy?
Sound, kinetic, chemical, gravitational potential, nuclear, elastic potential, thermal, light, electricity
1 of 34
What is work done?
Energy transferred when moving a force of 1 newton a distance of 1 metre in the direction of the force
2 of 34
How do we calculate work done?
Force (N) * Distance (m)
3 of 34
What is work done measured in?
Joules
4 of 34
How do we work out kinetic energy?
1/2 * m * v squared
5 of 34
How do we work out mass?
2Ek / v squared
6 of 34
How do we work out velocity?
square root of 2Ek/ m
7 of 34
What is the principle of conservation of energy?
Energy cannot be created or destroyed, only transferred
8 of 34
Work done is equal to......
Kinetic energy
9 of 34
How do you convert from km/h to m/s?
*1000/3600
10 of 34
How do you convert from km/min to m/?
*1000/60
11 of 34
How do you convert from m/min to m/s?
/60
12 of 34
How do you convert from km/s to m/s?
* 1000
13 of 34
Where is GPE stored?
In things high up, above the Earth's surface
14 of 34
How do we calculate GPE?
mass * gravity/acceleration/freefall * height
15 of 34
How do we convert from joules to kilojoules?
/1000
16 of 34
Why will a diver's kinetic energy as she hits the water be different to the GPE she gained climbing the diving board?
When she falls through the air she will have to do work against air resistance, energy is passed to the surroundings as heat/sound
17 of 34
Why is a bus more likely to cause harm to a person than a van?
The mass of the bus is larger so it has a greater KE
18 of 34
What is kinetic energy proportional to?
Velocity squared
19 of 34
What happens to the kinetic energy when the velocity squared doubles?
20 of 34
What is momentum?
The quantity of motion of a moving body, vector
21 of 34
How do we calculate momentum?
Mass * velocity
22 of 34
What is the principle of conservation of momentum?
The sum of the momentum before a collision is equal to the sum of momentum after a collision as long as there are no external forces acting
23 of 34
What three different types of collisions are there?
Elastic, inelastic and explosion
24 of 34
What is an elastic collision?
A collision where the objects do not stick together, momentum conserved unless external forces are acting, total energy and KE conserved
25 of 34
What is the formula for an elastic collision?
MaUa + MbUb = MaVa + MbVb
26 of 34
When two objects push each other apart, what do they move with?
Different speeds if they have unequal masses, equal and opposite momentum so their total momentum is zero
27 of 34
What is an inelastic collision?
A collision where the objects stick together, momentum is conserved unless external forces acting, KE not conserved but dissipate as thermal/sound
28 of 34
What is the formula for an inelastic collision?
MaUa + MbUb = (Ma + Mb) V
29 of 34
What is an explosion?
A collision where the objects move off in opposite directions, momentum before collision is always zero, momentum is conserved
30 of 34
What is the formula for an explosion?
0 = MaVa + MbVb
31 of 34
How do we work out the force?
Change in momentum / time
32 of 34
What do you write for momentum questions concerning safety?
Increases impact time, decreases rate of change in momentum/ acceleration, reduces the force
33 of 34
How do you use the idea of momentum to explain occurences?
Momentum is conserved, object is stationary, equal and opposite momentum, zero momentum before and after the jump, object has to go in opposite direction to other object
34 of 34

## Other cards in this set

### Card 2

#### Front

What is work done?

#### Back

Energy transferred when moving a force of 1 newton a distance of 1 metre in the direction of the force

### Card 3

#### Front

How do we calculate work done?

### Card 4

#### Front

What is work done measured in?

### Card 5

#### Front

How do we work out kinetic energy?