Physics : Motion and Forces

Question 1

What do vectors have?

Answer 1

Magnitude (size) and Direction

Question 2

What do scalars have?

Answer 2

Magnitude (size) but not Direction

Question 3

Distance is an example of what quantity?

Answer 3

Distance is a scalar quantity

Question 4

Speed and velocity both show what?

Answer 4

Both show how fast you are going

Question 4

Displacement is an example of what quantity?

Answer 4

Displacement is a vector quantity

Question 5

Acceleration shows what?

Answer 5

It shows how quickly you are speeding up

Question 6

What does uniform acceleration mean?

Answer 6

It means constant acceleration

Question 7

Name 3 examples of vector quantities:

Answer 7

Force, velocity, displacement, weight, acceleration and momentum

Question 8

Name 3 examples of scalar quantities:

Answer 8

Speed, distance, mass, energy, temperature and time

Question 9

What is displacement?

Answer 9

Displacement measures the distance and direction in a straight line from an object’s starting point to it’s finishing point.

Question 10

What is the equation that links speed, distance and time?

Answer 10

Distance travelled (m) = average speed (m/s) x time (s)

Question 11

What is the typical walking speed?

Answer 11

1.4 m/s

Question 12

What is the typical running speed?

Answer 12

3 m/s

Question 13

What is the typical cycling speed?

Answer 13

5.5 m/s

Question 14

What is the typical speed for cars in a built-up area?

Answer 14

13 m/s

Question 15

What is the typical speed for aeroplanes?

Answer 15

250 m/s

Question 16

What is the typical speed for cars on a motorway?

Answer 16

31m/s

Question 17

What is the typical speed for trains?

Answer 17

Up to 55 m/s

Question 18

What is the typical wind speed?

Answer 18

5-20 m/s

Question 19

What is the typical speed of sound in air?

Answer 19

340 m/s

Question 20

What is the typical speed of ferries?

Answer 20

15 m/s

Question 21

What is the equation that links acceleration, change in velocity and time?

Answer 21

Acceleration = change in velocity / time

Question 22

What is the equation for constant/uniform acceleration?

Answer 22

v2 - u2 = 2as

Question 23

What do distance/time graphs show?

Answer 23

They show how far something has travelled

Question 24

How do you find the speed from a distance/time graph?

Answer 24

The gradient is equal to the speed, so change in y over change in x

Question 25

What do velocity/time graphs show?

Answer 25

They show acceleration

Question 26

What does the gradient on a velocity/time graph represent?

Answer 26

The acceleration

Question 27

What does a flat section represent on a velocity/time graph?

Answer 27

A steady speed

Question 28

What do the uphill sections (/) on a velocity/time graph represent?

Answer 28

They represent acceleration

Question 29

What doe the downhill sections (\) on a velocity/time graph represent?

Answer 29

They represent deceleration

Question 30

How do you work out the distance travelled on a velocity/time graph?

Answer 30

The area under the curve is the distance

Question 31

What is needed to change motion?

Answer 31

A force

Question 32

What is Newton's First Law? | stationary and moving

Answer 32

If the resultant force on a stationary object is zero, the object will remain stationary. If the resultant force on a moving object is zero, it will carry on moving at the same velocity

Question 33

What is acceleration directly proportional to?

Answer 33

The resultant force

Question 34

What is the equation that links force, mass and acceleration?

Answer 34

Force = mass x acceleration

Question 35

Are weight and mass the same thing?

Answer 35

No

Question 36

What is weight?

Answer 36

Weight is the force acting on a object due to gravity

Question 37

Is weight a vector or scalar quantity?

Answer 37

Weight is a vector

Question 38

What is the equation that links weight, mass and gravity?

Answer 38

Weight (N) = mass (kg) x gravity (N/kg)

Question 39

What is centripetal force?

Answer 39

A force that keeps something moving in a circle

Question 40

What is inertia?

Answer 40

The tendency to keep moving with the same velocity

Question 41

What does an objects' inertia mass measure?

Answer 41

It measures how difficult it is to change the velocity of an object

Question 42

How can you calculate the inertia mass?

Answer 42

Use Newton's Second Law : m = F/a

Question 43

What is Newton's Third Law?

Answer 43

When two objects interact, the forces they exert on each other are equal and opposite.

Question 44

What is momentum?

Answer 44

It is the product of the object's mass and velocity

Question 45

How do you calculate momentum?

Answer 45

momentum (kg m/s) = mass (kg) x velocity (m/s) p = m x v

Question 46

Is momentum a vector or scalar quantity?

Answer 46

It is a vector quantity - it has size and direction

Question 47

What happens to the momentum when the mass or velocity of an object increases?

Answer 47

The momentum also increases

Question 48

What happens to the total momentum before and after an event in a closed system?

Answer 48

The total momentum before and after an event stays the same

Question 49

What is it called when the total momentum before and after an event stays the same?

Answer 49

Conservation of momentum

Question 50

What can force do to momentum?

Answer 50

Force can cause changes in momentum

Question 51

What happens when a resultant force acts on an object?

Answer 51

It causes a change in momentum

Question 52

What is the equation that links force, change in momentum and time?

Answer 52

Force (N) = change in momentum (kg m/s) / time (s) F = (mv-mu)/t

Question 53

If the change in momentum gets faster, what happens to the force?

Answer 53

The force gets bigger

Question 54

What is the thinking distance?

Answer 54

The distance the car travels in the driver's reaction time

Question 54

What is stopping distance?

Answer 54

It is the thinking distance + the braking distance

Question 55

What affects the thinking distance?

Answer 55

Reaction time - distance is increased by tiredness, alcohol, drugs and distractions Speed - faster you're going the further you will travel during your reaction time

Question 56

What is the braking distance?

Answer 56

The distance taken to stop once the brakes have been applied

Question 57

What affects the stopping distance?

Answer 57

Speed - the faster you're going the longer it takes to stop Mass of car - car full of people won't stop as quickly as an empty one Condition of brakes - worn or faulty ones won't brake with as much force Friction between tyres and road - if the tyre tread is worn or there is dirty/icy/wet conditions then you are likely to skid

Question 58

What is the equation that measures the energy transfer from the car to it's brakes?

Answer 58

Energy in car's kinetic energy store = work done by brakes 0.5 x m x v^2 = F x d