P10

Question 1

Typical value for the speed of sound?

Answer 1

330m/s

Question 2

What can be said about the resultant force acting on an object when it is falling at terminal velocity?

Answer 2

The resultant force is zero

When at terminal velocity, the object is moving at a constant speed and so isnt accelerating

Question 3

What does newtons second law of motion state?

Answer 3

The acceleration of an object is proportional to the resultant force and inversely proportional to the mass of an object

Question 4

What is inertia?

Answer 4

The tendency of an object to continue in its state of rest

Question 5

What is inertial mass?

Answer 5

A measure of how difficult it is to change a given object’s velocity
The ratio of force over acceleration

Question 6

What is stopping distance of a vehicle equal to?

Answer 6

The sum of thinkingdistance and braking distance

Question 7

For a given braking distance, if the vehicle’s speed is increased, what can be said about its stopping distance?

Answer 7

The stopping distance is increased with an increase in speed

Question 8

Give three factors which can affect a driver’s reaction time

Answer 8

1) tiredness
2) drugs
3) alcohol

Question 9

Give 2 factors which may affect braking distance?

Answer 9

1) wet/icy road conditions

2) poor tyre/brake conditions

Question 10

Describe the energy transfers that take place when a car applies its brakes?

Answer 10

Work is done by the frcitiom force between teh brakes and wheel
Kinetic energy is converted to heat and is dissipated to the surroundings

Question 11

State two consequences of a vehicle undergoing very large decelerations?

Answer 11

1) kinetic energy converted to heat is very high causing braked to overheat
2) loss of control of the vehicle

Question 12

In a closed system, what can be said about the momentum before and after a collision?

Answer 12

Total momentum before is equal to the total momentum afterwards

Question 13

State an equation linking change in momentum, time And force

Answer 13

Momentum = force x time

Question 14

What quantity is equal to the force experienced in a collision?

Answer 14

The rate of change of momentum

Question 15

Explain how a seatbelt improves a passneger’s safety during a collison?

Answer 15

Seatbelts increase the time over which the force is applied,reducing the rate of change of momentum and therefore reducimg the force experienced

Question 16

Explain the relationship between the fprce applied and the extensiom of an elastic object?

Answer 16

The extesnion is directly proportional to the froce apllied

Question 17

State the equation relating force, spring constant and extension

Answer 17

Force= speing constant x extension

Question 18

What type of energy is stored in a sepimg when its strecthed?

Answer 18

Elastic potentional energy

Question 19

What can extension be replaced with in the equation for spring force?

Answer 19

Compression