P10 - Forces & Motion 2️⃣✅

Question 1

What is breaking distance?

Answer 1

The distance travelled by a vehicle whilst its under the breakign force

Question 2

What is the principle of conservation of momentum?

Answer 2

That in a closed system, the total momentum before an event is equal to the total momentum after the event. Momentum is conserved in any collision /explosion, provided no external forces act on the objects that collide /explode

Question 3

What does directionally proportional mean?

Answer 3

When a graphs line of best fit is straight and goes through the origin

Question 4

What does proportional mean?

Answer 4

When a graphs line is straight

Question 5

What does it mean if a material is elastic/ what is elastic deformation?

Answer 5

If a material is elastic, it means its able to regain its shape after it has been squashed or stretched

Question 6

What does extension mean?

Answer 6

The increase in length of a spring/ strip of material from its original length

Question 7

What does inertia mean?

Answer 7

The tendency of objects to continue in their state of rest or of uniform motion

Question 8

What is the limit of proportionality?

Answer 8

The limit at which an elastic material can be stretched without deforming

Question 9

What is mass?

Answer 9

Mass is a scalar quantity and is the amount of matter in an object

Question 10

What is weight?

Answer 10

Weight is a force (vector) and is the force of gravity on an object

Question 11

What is terminal velocity?

Answer 11

The velocity reached by an object when the air resistance on it is equal to its mass / the force making it move.

Question 12

What is the equation for momentum?

Answer 12

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

Question 13

What is momentum?

Answer 13

Momentum is a quality possessed by masses in motion and is a measure of now difficult it is to stop something moving

Question 14

What is stopping distance?

Answer 14

The sum of the thinking distance and breaking distance

Question 15

What is thinking distance?

Answer 15

The distance the vehicle travesl during the drivers reaction time

Question 16

What are the units for momentum?

Answer 16

Kgm/s

Question 17

What is the equation for acceleration?

Answer 17

A (acceleration m/s2 ) = v ( change in velocity m/s) / t (time s)

Question 18

What type of force is speed?

Answer 18

Scalar ( just speed not diretion)

Question 19

What type of force is velocity?

Answer 19

Vector ( speed and direction)

Question 20

What type of force is momentum?

Answer 20

Vector (speed and direction)

Question 21

What is tension?

Answer 21

A pulling force

Question 22

What is compression?

Answer 22

A squashing force

Question 23

What is inelastic deformation?

Answer 23

When an object is stretched and stays stretched for example blue tack

Question 24

What is the equation for extension?

Answer 24

Extension = new length - original length

Question 25

What is a fiducal marker?

Answer 25

An object placed in the field of view of 2 objects that are not touching e-g spring & metre stick to measure/ see length accurately.

Question 26

What is parallax error?

Answer 26

An error that occurs due to incorrect positioning of the eyes while taking a reading or measurement

Question 27

What is Hooke’s law?

Answer 27

The extension of an object is directly proportional to the force that is applied to it provided that the limit of proportionality is not exceeded.

Question 28

What is the equation for Hooke’s law?

Answer 28

F (force N) = k (spring constant N/m) x e (extension m)

Question 29

What is Newton’s second law?

Answer 29

Acceleration of an object is proportional to the resultant force on the object and inversely proportional to the mass of the object

Question 30

What does inversely proportional mean?

Answer 30

Inversely proportional means when the value of one quantity increases the other decreases and vice versa. It means that two quantities behave opposite in nature.

Question 31

What is the equation that links with Newtons second law?

Answer 31

F (force N) = m (mass kg) x a (acceleration m/s2)

Question 32

What is the inertial mass of an object?

Answer 32

The inertial mass of an object is s a measure of how difficult it is to change the velocity of an object

Question 33

What is the equation for inertial mass?

Answer 33

Inertial mass = f (force N) / a (acceleration m/s2)

Question 34

How do you work out stopping distance?

Answer 34

Stopping distance = thinking distance + breaking distance

Question 35

How do you work out collision questions?

Answer 35

To work out collisions you first would work out the momentum of each object using
p = m x v. Then you would work out the total mass of each object by adding the masses up. Then finally you would add up the momentums of each and use the velocity equation v = p/m to do the total momentum over the total mass to get the velocity of the collision (question can ask for mass so just rearrange method for mass)

Question 36

How do you work out recoil velocity questions?

Answer 36

To work out recoil velocity questions you would first work out the momentum of the moving objects e.g. cannon ball from a cannon using p = m x v. Then to work out the recoil velocity you would use the equation v = p/m and use the moving object (cannon ball) momentum and the mass of the object that launched/ hit it (cannon). & put a minus because it’s recoil

Question 37

What is Newtons 3rd Law?

Answer 37

for every action (force) in nature there is an equal and opposite reaction

Question 38

What is the typical value for walking?

Answer 38

1.5m/s

Question 38

What is the typical value for running?

Answer 38

3m/s

Question 39

What is the typical value for cycling?

Answer 39

6m/s

Question 40

What is the typical value for the speed of sound in air?

Answer 40

330m/s

Question 41

What things can typically affect a drivers reaction time?

Answer 41

alcohol & drugs

Question 42

What factors an affect breaking distance?

Answer 42

• adverse road and weather conditions
• poor condition of the vehicle

Question 43

What does adverse road conditions infer?

Answer 43

That the road conditions are icy or wet

Question 44

What does poor condtion of vehicle infer?

Answer 44

That the vehicles breaks or tyers are faulty (cannot be applied to any other part of vehicle for marks)

Question 45

The ________ the speed of a vehicle the ________ the braking force needed to stop the vehicle in a certain distance.

Answer 45

The greater the speed of a vehicle the greater the braking force needed to stop the vehicle in a certain distance.

Question 46

Explain how a seatbelt works as a safety feature

Answer 46

• Due the design of the belt energy due to a collision is spread out by the belt over the chest, pelvis and shoulders
• when in collision the person moves against the seatbelt, exerting a force upon it; according to newtons 3rd law the seatbelt exerts an equal and opposite force back against the person, consequently creating a controlled deacceleration them and keeping them save/ preventing them going through the windshield
• decreases elastic potential energy - 1/2 x k x e2

Question 47

Explain how an air bag works as a safety feature

Answer 47

• utilises an accelerometer (elecric chip that measures change in acceleration) and an imact sensor to make sure it deploys at correct time
• Air bag deploys instantly after collision to increase the time for the persons momentum to reach zero so the initial impact is significantly less
• links to - force = change in momentum / change in time

Question 48

Explain how the crumple zone works as a safety feature

Answer 48

• crumple zones area at front of car designed to absorb impact energy during a collison so that most of the energy from the crash is dissapated across these zones rather than passenger compartment to prevent harm
• In a crash the crumple zones help to transfer some of the cars kinetic energy into controlled deformation; increasing chances of vehicle damage but greatly decreasing chances of damage to passengers
• overall also increase time which collision takes place which consequently reduces the change in momentum (force = change in momentum / change in time)

Question 49

What could a large decceleration lead to?

Answer 49

A large deceleration may lead to brakes overheating and/or
loss of control