P5 - Forces

Question 1

What are scalar quantities?

Answer 1

Only have magnitude

Question 2

What are the five examples of scalar quantities?

Answer 2

Speed
Distance
Temperature
Mass
Time

Question 3

What are vector quantities?

Answer 3

Have magnitude and a direction

Question 4

What are the five examples of vector quantities?

Answer 4

Force
Velocity
Displacement
Acceleration
Momentum

Question 5

What is the definition of a force?

Answer 5

A push or a pull on an object caused by it interacting with something.

Question 6

What is the difference between a contact and non - contact force?

Answer 6

Contact has to be touching, non- contact does not.

Question 7

What are three examples of a contact force?

Answer 7

Friction
Tension
Air resistance

Question 8

What are three examples of a non - contact forces?

Answer 8

Electrostatic force
Gravitational force
Magnetic force

Question 9

What is the definition of weight?

Answer 9

The force that acts on an object due to gravity.

Question 10

What is the definition of equilibrium?

Answer 10

When’s the forces acting on an object are balanced and the resultant force is zero.

Question 11

What is the definition of resultant force?

Answer 11

A single force of hay can replace all the forces acting on an object to give the same effect as all original forces acting together.

Question 12

When is work done done on an object?

Answer 12

When a force moves on an object from one point to another, energy is transferred and work is done on the object.

Question 13

What has to be done to change the shape of a spring?

Answer 13

More than one force has to act on a stationary object to change its shape.

Question 14

What is the extension of a stretched spring directly proportional to?

Answer 14

The load or force applied

Question 15

What happens when the force gets too big?

Answer 15

The extension is no longer proportional to the force.

Question 16

What are the typical speeds for walking, running, cycling, a car, a train, a plane and sound?

Answer 16

1.5m/s
3m/s
6m/s
25m/s
30m/s
250m/s
330m/s

Question 17

What is the definition of acceleration?

Answer 17

Change in velocity in a certain time

Question 18

What is the definition of friction?

Answer 18

A force that acts to oppose an objects motion. It always acts in the opposite direction to movement.

Question 19

What is the definition of a drag?

Answer 19

The frictional force caused by any fluid on a moving object.

Question 20

What are three factors affecting reaction times?

Answer 20

Tiredness
Drugs
Alcohol

Question 21

What is the ruler drop test?

Answer 21

1. Get someone to hold ruler so zero is between thumb and forefinger
2. Ruler gets dropped without warning. Catch it as quickly as possible.
3. Use distance ruler fell to calculate the reaction time.

Question 22

What does it mean the longer the distance?

Answer 22

The longer the reaction time

Question 23

What is the thinking distance?

Answer 23

How far the vehicle moves during driver’s reaction time

Question 24

What is the braking distance?

Answer 24

The distance taken to stop whilst brakes are applied

Question 25

What 2 factors can increase thinking distance?

Answer 25

1. Faster vehicle speed 2. Slow driver reaction times

Question 26

What 4 factors increase braking?

Answer 26

1. Faster vehicle speed 2. Wet and icy weather 3. Poor road surface 4. Damaged or worn brakes or tyres

Question 27

What work done is done when stopping?

Answer 27

1. Driver brakes, causing brake pads to be pressed onto wheels 2. Friction between them causes work to be done 3. Energy transferred from kinetic energy stored of wheels to thermal energy stores of brakes 4. Brakes, heat up

Question 28

What does it mean the bigger the stopping distance?

Answer 28

More space drivers need to leave between their car and one in front

Question 29

What if speed doubles?

Answer 29

Thinking distance doubles and braking distance quadruples.

Question 30

What is the conservation of momentum?

Answer 30

In a closed system, the total momentum before an event (eg collision) equals total momentum after an event.

Question 31

What are five safety features that increase time for change in momentum?

Answer 31

Air bags Seat belts Cushioned playground flooring Crash mats Bike helmets

Question 32

How do air bags increase time for change in momentum?

Answer 32

1. Inflates during car wash 2. Compressing air decreases velocity over a longer time compared to hitting dashboard 3. Rate of change of momentum = smaller 4. Forces felt are smaller so less severe injuries