Physics - Forces 2

Question 1

What is the speed of walking?

Answer 1

1.5 m/s

Question 2

What is the speed of running?

Answer 2

3 m/s

Question 3

What is the speed of cycling?

Answer 3

6 m/s

Question 4

What is the speed of sound in the air?

Answer 4

330 m/s

Question 5

What is non-uniform motion?

Answer 5

Motion when the speed isn’t constant

Question 6

How do you calculate the average speed for non-uniform motion?

Answer 6

Use the formula:
Average speed = Total distance / total time

Question 7

What’s the difference between speed and velocity?

Answer 7

Speed is scalar and velocity is vector

Question 8

What is displacement?

Answer 8

Straight line distance between the start and end points of a journey. Vector

Question 9

What is distance?

Answer 9

The length of the total journey. Scalar

Question 10

How do you calculate the average velocity?

Answer 10

Velocity = displacement / time

Question 11

What is acceleration?

Answer 11

The rate at which an objects velocity changes. m/s/s

Question 12

How do you calculate acceleration?

Answer 12

Acceleration = change in velocity / time

Question 13

How can something be moving at a constant speed but accelerating?

Answer 13

Velocity is a vector so if and object is moving in a circular motion, it is accelerating

Question 14

How do you find the speed of an object in uniform motion?

Answer 14

Find the gradient of the straight line

Question 15

How do you find the speed of an object in non-uniform motion?

Answer 15

Draw a tangent and take the gradient

Question 16

How do you find the distance on a distance time graph?

Answer 16

The area under the line

Question 17

What is Newton’s first law?

Answer 17

If no resultant force acts on an object then its motion won’t change

Question 18

What is Newton’s second law?

Answer 18

Acceleration is proportional to the resultant force acting on it. It’s inversely proportional to the mass

Question 19

What is inertial mass?

Answer 19

A measure of how difficult it is to change and object’s velocity

Question 20

What is the inertial mass equation?

Answer 20

Inertial mass = resultant force / acceleration

Question 21

How can Newtons second law be verified experimentally?

Answer 21

The ramp, trolley one. Things to remember:
- Keep the mass of the system the same
- Have the ramp slightly tilted to account for friction

Question 22

What is stopping distance?

Answer 22

The total distance required to stop a vehicle.
Thinking distance + braking distance

Question 23

What factors affect thinking distance?

Answer 23

Speed, drugs, alcohol, tiredness and distractions

Question 24

What factors affect braking distance?

Answer 24

Speed, condition of the road, condition of the brakes/tyres

Question 25

What energy transfers take place when a car brakes?

Answer 25

Kinetic store of the vehicle is mechanically transferred to the thermal store of the brakes

Question 26

What happens if the brakes are applied too quickly?

Answer 26

Brakes can overheat and fail. If the vehicle is out of control it can skid

Question 27

What is momentum?

Answer 27

The tendency of an object to remain in motion

Question 28

How do you find momentum?

Answer 28

Momentum = mass x velocity

Question 29

What is conservation of momentum?

Answer 29

In a closed system the total momentum before an event is equal to the total momentum after an event

Question 30

What do forces do to momentum?

Answer 30

When a resultant force acts on an object there's a change in momentum

Question 31

How are seatbelts, airbags and crumple zones useful?

Answer 31

They increase the impact time in a collision. This reduces the rate of change of momentum and reduces the impact force on the car