Term 1

Question 1

Newton’s First Law

Answer 1

If the resultant force acting on an object is zero:
- If the object is stationary, it will remain stationary
- If the object is moving, it will continue to move at the same speed in the same direction

Question 2

Newton’s Third Law

Answer 2

When 2 objects interact, the forces they exert on each other are equal and opposite i.e. weight, a tennis ball pulls on the Earth and the Earth pulls on the ball with equal force

Question 3

Example of a Newton 3 pair

Answer 3

A ball on a table, the ball pushes on the table and the table pushes on the ball with equal and opposite force

Question 4

When might Newton’s 3rd law apply?(4)

Answer 4

-There are two ‘objects’
-The forces are of the same type
-The forces are equal in magnitude (also applies to balanced forces)
-The forces are opposite in direction (also applies to balanced forces)

Question 5

Inertial mass

Answer 5

A measure of how difficult it is to change the velocity of an object

Question 6

Newton’s Second Law

Answer 6

Resultant force = mass x acceleration
F = ma

Question 7

Acceleration

Answer 7

Rate of change in velocity, change in velocity per second

Question 8

Acceleration is…

Answer 8

-Proportional to the resultant force acting on an object
-Inversely proportional to the mass of an object

Question 9

Acceleration formula

Answer 9

a = v-u/t

Question 10

Uniform motion

Answer 10

Acceleration is constant

Question 11

Symbols for motion(4)

Answer 11

s - displacement in m
u - initial velocity in m/s
v - final velocity in m/s
a - acceleration in m/s squared

Question 12

Initial velocity

Answer 12

Speed of an object before acceleration/deceleration

Question 13

Final velocity

Answer 13

Speed of an object after acceleration/deceleration

Question 14

When an object is accelerating uniformly…

Answer 14

v squared - u squared = 2as

Question 15

When there is no air resistance, gravity gives a falling object an acceleration of…

Answer 15

9.8m/s squared

Question 16

When a ball is thrown upwards…

Answer 16

it decelerates and acceleration is then -9.8m/s squared

Question 17

What do velocity-time graphs show

Answer 17

How the velocity of a moving object changes over time

Question 18

When dealing with non-constant acceleration, what acronym do you use?

Answer 18

F(orces)
R(esultant force)
A(cceleration)
V(elocity)

Question 19

How do the forces acting on a skydiver change from when he jumps out of the plane to before he deploys the parachute(5)?

Answer 19

-As soon as the skydiver jumps out of the plane, the only force acting on him is the downward force of weight (this is due to gravity, this force will never change throughout the scenario)

-This means his resultant force is his weight (ma = mg, mass cancels out so the gravitational field strength = acceleration), so he is accelerating at 9.8m/s squared

-As the skydiver falls, his velocity increases, and therefore the amount of the upward force of drag he experiences increases

-This drag reduces his resultant force (Resultant force = weight
- drag), therefore reducing his acceleration

-At a certain point, the drag that was increasing will be equal to the weight, making his resultant force zero, and with Newton’s first law that means his acceleration is zero and he has reached terminal velocity and is now travelling at constant speed

Question 20

How do the forces acting on a skydiver change from when he jumps out of the plane to after he deploys the parachute?

Answer 20

-The skydiver then opens their parachute, causing the air resistance to massively increase and making the drag greater than the weight. This causes the skydiver’s to decelerate and his velocity decreases

• However, since the velocity has decreased, his air resistance will also decrease and eventually the forces will balance again and he will once again achieve terminal velocity, this time at a lower speed

Question 21

Terminal velocity

Answer 21

The maximum speed of the object, reached when the forces moving the object are balanced with the frictional forces i.e. air resistance

Question 22

Stopping distance

Answer 22

The distance needed for a vehicle given speed to stop

Question 23

Stopping distance is…

Answer 23

Thinking distance + Braking distance

Question 24

Thinking distance

Answer 24

Distance the vehicle travels during the driver’s reaction time

Question 25

Braking distance

Answer 25

The distance a vehicle travels in the time after the driver has applied the brake until the vehicle comes to a stop

Question 26

Reaction time (in stopping distance topic)

Answer 26

Time taken for driver to spot the hazard, make a decision and move their foot to the brake

Question 27

Factors affecting thinking distance(7)

Answer 27

-Age
-Tiredness
-Drugs(including legal ones!)
-Focus/Presence of distractions
-Speed
-Phones
-Weather i.e. rain impeding driver’s vision, fog

Question 28

Factors affecting braking distance(4)

Answer 28

-Mass of vehicle
-Tyre condition(Tyres in bad condition will reduce friction between tyre and road)
-Road condition i.e. icy, wet (reduces friction between tyre and road
-Condition of brakes

Question 29

When thinking distance at different speeds was compared on a graph, the graphs gradient was…

Answer 29

straight