Momentum

Question 1

What is momentum

Answer 1

It is a quantity possessed by masses in motion and is the measure of difficult it is to stop the object moving

Question 2

Equation for momentum

Answer 2

Momentum = mass (kg) x velocity (m/s)

p=mv

Question 3

Relationship?

Answer 3

Directly proportional- the higher the mass, the higher the momentum whilst moving

Question 4

Equation for rate of increase of momentum

Answer 4

 t 

mu= initial momentum
mv= final momentum 

aka force x time= momentum

Question 5

Rule of momentum

Answer 5

momentum before collision = momentum after collision

Question 6

Elastic collision

Answer 6

These are collisions in which NO kinetic energy is lost by bring transformed into other forms eg molecules in a container of air

Question 7

Inelastic collision

Answer 7

When 2 objects collide and stick together because all of the kinetic energy is lost

Question 8

Partially elastic collsion

Answer 8

Ball bouncing of ground- still has kinetic energy but loses some hence each bounce is smaller then the last

Question 9

Explosions

Answer 9

Momentum before and after is unchanged however there is a massive increase in kinetic energy

Question 10

How do rockets work?

Answer 10

Rocket motors product continuous, controlled explosions which force fast moving gas out the back of the rocket
The spacecraft gains the same amount of momentum in the opposite direction to where the gases are moving out

Question 11

10 safety features of a car

Answer 11

Front crumple zone 
Engine block
Safety glass
Air bags
Seat belts
Safety cell
Rear crumple zone
Side impact bars
Steering wheel column 
Anti lock braking system

Question 12

Crumple zones

Answer 12

Allows energy to dissipated before impact to passengers and slows the deceleration of the car

Question 13

Engine block

Answer 13

Engine block slides under the passenger safety cell

Question 14

Safety glass

Answer 14

Windshield glass is designed to fracture into rounded pieces instead of shattering

Question 15

Air bags

Answer 15

Automatically inflate within 1/100th of a second to cushion passengers

Question 16

Seat belts

Answer 16

Lock to keep passengers in seat when car rapidly decelerates

Question 17

Passenger safety cell

Answer 17

Rigid cage prevents roof collapsing and crushing passengers

Question 18

Side impact bars

Answer 18

Strong bars inside door frame in case car impacted on side

Question 19

Steering wheel column

Answer 19

Collapsable section of steering wheel column reduces injury to driver form this

Question 20

Antilock braking system

Answer 20

Wheels don’t lock as this can cause skidding- active computer system rapidly pumps the brakes

Question 21

What principle do crumple zones and seat belts work under

Answer 21

force=mass x acceleration and
force = change in momentum/time
first equation- mass is constant so if you decrease the acceleration, you reduce the force
second equation- time is constant so if you increase the time, the force decreases
both reduce the impact on the passenger by increasing the collision time

Question 22

Newton’s law of motion

Answer 22

1. Things don’t speed up, slow down or change direction unless you push/pull them
2. The bigger the force acting on an object, the faster it will speed up
3. Objects with larger masses require larger forces in order to make them accelerate at the same rate as objects with smaller masses
4. When you push something, it pushes back just as hard in the opposite direction