Topic 3 - Motion and Forces

Question 1

What is meant by the term ‘speed’?

Answer 1

How fast you’re going with no regard to the direction.

Question 2

What is meant by the term ‘velocity’?

Answer 2

Velocity is how fast you’re going but must also have a direction.

Question 3

What is meant by the term ‘displacement’?

Answer 3

The distance in a particular direction.

Question 4

What makes something a vector quantity?

Answer 4

A measurement that has magnitude (size) and direction.

Question 5

What is the formula for speed?

Answer 5

Speed=distance/time

Question 6

What is meant by the term ‘acceleration’?

Answer 6

A measure of how quickly velocity is changing. This can be a change in speed or a change in direction or both. (Only calculate change in speed).

Question 7

What is the formula for acceleration?

Answer 7

Acceleration=change in velocity/time taken

Question 8

What is the symbol equation for acceleration?

Answer 8

(v-u)/t

Question 9

What does the letter u represent?

Answer 9

The initial velocity.

Question 10

What does the letter v represent?

Answer 10

The final velocity.

Question 11

What is the unit for acceleration?

Answer 11

m/s2(squared)

Question 12

What are speed and velocity measured in?

Answer 12

m/s or km/h or mph

Question 13

On a distance-time graph, what are the x and y axis labels?

Answer 13

x is time

y is distance

Question 14

On a distance-time graph, what does the gradient represent?

Answer 14

Speed

Question 15

On a distance time-graph, when the line is flat, what does this represent?

Answer 15

Not moving, stopped

Question 16

On a distance-time graph, what does it meant when it is going downwards?

Answer 16

It is going back towards the start point

Question 17

On a distance-time graph, what do curves represent?

Answer 17

Acceleration or deceleration

Steepening curve means speeding up, levelling off curve means slowing down.

Question 18

How do you calculate speed from a distance time graph?

Answer 18

vertical/horizontal (bearing in mind the scales)

Question 19

What are the labels for the x and y axis on a velocity-time graph?

Answer 19

x is time

y is velocity

Question 20

On a velocity-time graph, what does the gradient represent?

Answer 20

The acceleration

Question 21

On a velocity-time graph, what do the flat sections represent?

Answer 21

Steady speed

Steeper the graph, the greater the acceleration

Question 22

On a velocity-time graph, what do the uphill sections show?

Answer 22

Acceleration

Question 23

On a velocity-time graph, what do the downhill sections represent?

Answer 23

Deceleration

Question 24

Using a distance-time graph, how do you work out the distance travelled in a certain amount of time?

Answer 24

Work out the area underneath that time section

Question 25

On a velocity-time graph, what does a curve mean?

Answer 25

Changing acceleration

Question 26

How do you work out the acceleration using a velocity-time graph?

Answer 26

Gradient therefore vertical/horizontal

Question 27

When force arrows are drawn, what do the lengthen and direction represent?

Answer 27

Length it the size of the force and direction shows the direction of the force

Question 28

What does it mean if the arrows come in opposite pairs and they the same size?

Answer 28

The forces are balanced

Question 29

Describe the forces on a stationary object

Answer 29

Forces are balanced. Weight (gravity) is acting downwards with an equal reaction force going upwards of reaction. There must also be equal, or no horizontal forces.

Question 30

What happens to an object if one force doesn't have a reaction force?

Answer 30

It accelerates

Question 31

Describe the forces when an object is moving horizontally or vertically at a steady speed.

Answer 31

All forces are equal

Question 32

Describe the forces when an object is accelerating

Answer 32

You have a resultant force, shown by one arrow being longer than the other. The bigger the unbalanced force, the greater the acceleration.

Question 33

What is meant by the term 'weight' and what it is measured in?

Answer 33

Weight is caused by the pull of gravity and is measured in Newtons.

Question 34

What is meant by the term 'mass' and what is it measured in?

Answer 34

Mass is not a force. Mass is measured in kg and is how much 'stuff' is in an object.

Question 35

What is the equation to work out weight?

Answer 35

Weight=massxgravitational field strength (W=mxg)

Question 36

Describe what happens to accelerating objects in space

Answer 36

Gravity makes all objects accelerate at the same rate, no matter on their size. This is because there's no air resistance in space, so there is only the force of gravity. Larger objects don't have a larger air resistance like on earth and therefore accelerate at the same speed as smaller objects

Question 37

Describe how objects falling reach terminal velocity when falling through somewhere with air resistance.

Answer 37

At first, objects falling have more force (weight) accelerating than resistance slowing them down. As the speed increases, the air resistance increases too, gradually reducing air resistance until weight it equal to air resistance. When these forces are balanced, the object won't accelerate any more, as it has reached it's maximum speed or terminal velocity.

Question 38

What is the rule for when you exit force on an object?

Answer 38

If object A exerts a force on object B then object B exerts the exact opposite force on object A. (At the exact moment the two objects touch)

Question 39

What happens if there is no resultant force?

Answer 39

If there is zero resultant force acting on a body (the forces are balanced) then the body will remain at rest, or else if it's already moving it will just carry on at the same velocity.

Question 40

How does a resultant force affect an object?

Answer 40

If the resultant force acting on a body is not zero, it will accelerate in the direction of the resultant force.

Question 41

What are the five from acceleration can be in?

Answer 41

Starting, stopping, speeding up, slowing down, changing direction

Question 42

What is the equation for force?

Answer 42

Force=mass x acceleration