Unit 2 - Motion And Forces

Question 1

How might someone have constant speed but a changing velocity

Answer 1

Changing direction

Question 2

Why is acceleration a vector quantity

Answer 2

It has a direction and magnitude

Question 3

Then a diagram, what represents the size of a force

Answer 3

By the length of the arrow

Question 4

What is the thrust?

Answer 4

The push force on an object

Question 5

What is the resultant force

Answer 5

The force on an object that creates the overall effect

Question 6

Wha are balanced forces

Answer 6

When the resultant force equals 0

Question 7

What are unbalanced forces

Answer 7

When the resultant forces don’t equal 0

Question 8

What is Newton’s first law?

Answer 8

A moving object will continue to move at the same speed and direction unless an external force acts on it
A stationary object will remain at rest unless an external force acts on it

Question 9

What forces change the velocity of an object

Answer 9

Unbalanced forces

Question 10

What is the centripetal force?

Answer 10

A force that acts on a moving object in a circular path and is directed towards the centre which the object is circuling

Question 11

What forces can make objects move in circular paths (3)

Answer 11

Centripetal force, gravity and friction

Question 12

For a motorbike, what provides the centripetal force?

Answer 12

Friction between the tyres and the road

Question 13

What is mass

Answer 13

The quantity of matter in an object

Question 14

What is weight?

Answer 14

A measure of the pull of gravity on an object

Question 15

What are the units for mass

Answer 15

Kg

Question 16

What are the units for weight?

Answer 16

Newton’s (N)

Question 17

How can weight be measured

Answer 17

Using a force meter

Question 18

What is the GFS on Earth?

Answer 18

10N/Kg

Question 19

What is the symbol equation for weight?

Answer 19

W = m x g

Question 20

How can a skydiver stop accelerating

Answer 20

Air resistance increases with speed so after a few seconds, the air resistance balances her weight

Question 21

What is Newton’s second law?

Answer 21

The acceleration in the direction of the resultant force depends on:
The size of the force
The mass of the object

Question 22

What is the odd equation for force?

Answer 22

Force = mass x acceleration

Question 23

What is the symbol equation for force

Answer 23

f = m x a

Question 24

What is inertial mass

Answer 24

The force on an object divided by the acceleration the force produces

Question 25

Explain the core practice - investigating acceleration

Answer 25

Put a trolley on a ramp and adjust the slope so it begins to move on its own. Set up the light gates and the pulley and string. Put a piece of card on the trolley and measure it. Find the mass of the trolley Put a mass at the other end of the string Release the trolley and write down the speed from the datalogger Write down the time for it to get from each light gate Put a mass on top of the trolley and repeat

Question 26

For the core practical - investigating acceleration, how can the experiment be altered to investigate the effect of force rather than the effect of mass?

Answer 26

Stack masses on the trolley and each time, transfer one to the other end of the string

Question 27

What is Newton’s third law?

Answer 27

For every action, there is an equal and opposite reaction

Question 28

What are action-reaction forces?

Answer 28

A pair of forces on the two interactive objects

Question 29

What are 3 factors of action-reaction forces?

Answer 29

Same size, opposite directions and same type

Question 30

What is an equilibrium situation for forces?

Answer 30

When nothing is moving equal forces e,g pulling a rope

Question 31

What is the difference between action-reaction forces and balanced forces?

Answer 31

Balanced forces act on the same object (force of ground on dog and force of gravity on dog) Action-reaction forces act on different objects (from ground on dog and on dog from ground)

Question 32

Give 2 factors of action-reaction forces in a collision

Answer 32

Same size | Different effects due to different masses

Question 33

What is momentum

Answer 33

A measure of the tendency of an object to keep moving or how hard it is to stop it moving

Question 34

Why is momentum a vector quantity

Answer 34

It depends on velocity

Question 35

What is the symbol equation for momentum

Answer 35

p = m x v

Question 36

What is the second symbol equation for force involving velocity

Answer 36

f = mv - mu / t

Question 37

What is conservation of momentum?

Answer 37

When moving objects collide, the total momentum from before the collision is the same as after the collision if there are no external forces

Question 38

What is thinking distanc?

Answer 38

The distance the object travels between seeing the problem and reacting

Question 39

What is the braking distance

Answer 39

The distance an object travels while the brakes are working to stop it moving

Question 40

What is the stopping distance of a vehicle?

Answer 40

The sum of the thinking and braking distance

Question 41

The time between a person detecting a stimulus and their response

Answer 41

What is the reaction time?

Question 42

What can reaction times be measured using?

Answer 42

Computers

Question 43

What can slow someone’s reaction time? (4)

Answer 43

If they are tired, I’ll, taking drugs or distracted

Question 44

What can increase the braking distance? (2)

Answer 44

Friction (If the brakes are worn out) | Mass (heavier vehicle needs more force)

Question 45

What is work done

Answer 45

The energy transferred by a force acting over a distance

Question 46

What is the word equation for work done

Answer 46

Work done = force x distance

Question 47

What is the energy stored in a moving object?

Answer 47

Kinetic energy

Question 48

What is the word equation for kinetic energy

Answer 48

Kinetic energy = mass x velocity^2 / 2

Question 49

When an object stops, what is the kinetic energy transferred to?

Answer 49

Other energy stores by the braking force

Question 50

What is the kinetic energy equal to?

Answer 50

The work done

Question 51

What are crumple zones?

Answer 51

Zones built into the front of a car which absorb the impact of a collision making the deceleration less

Question 52

What is the use of airbags?

Answer 52

They increase the time it takes for a persons head to stop in a collision

Question 53

What is the use of seatbelts

Answer 53

To hold the passenger into the car

Question 54

Why is it best to increase the time for something to hit the ground for safety?

Answer 54

Because it reduces the force on it

Question 55

What does the force in a collision depend on?

Answer 55

The change in momentum as the car comes to a stop

Question 56

What does a negative sign show for a force?

Answer 56

It is acting in the opposite direction to the original direction