Chapter 3: Motion

Question 1

What is kinematics?

Answer 1

Kinematics is the science of describing the motion of objects

Question 2

What is velocity? What is the equation?

Answer 2

Velocity is the rate of change of displacement

Average Velocity = Displacement/Time

Question 3

What is speed on a distance-time graph?

Answer 3

Speed is the gradient

Question 4

What is acceleration?

Answer 4

Acceleration is the positive rate of change of velocity. On a displacement-time graph, it appears as the gradient becoming more positive

Question 5

What is deceleration?

Answer 5

Deceleration is the negative rate of change of velocity. On a displacement-time graph, it appears as the gradient becoming more flat

Question 6

What is distance on a speed-time graph?

Answer 6

Area underneath the graph

Question 7

What is the equation for acceleration?

Answer 7

Final velocity - Initial Velocity /// Time

Question 8

What is the SUVAT equation without ‘s’?

Answer 8

v = u + at

Question 9

What is the SUVAT equation without ‘v’?

Answer 9

s = ut + 1/2*(at²)

Question 10

What is the SUVAT equation without ‘a’?

Answer 10

s = 1/2(u+v)t

Question 11

What is the SUVAT equation without ‘t’?

Answer 11

v² - u² = 2as

Question 12

What is the SUVAT equation without ‘u’?

Answer 12

s = vt - 1/2*(at²)

Question 13

What does constant thrust result in?

Answer 13

Constant thrust is a constant force with a constant acceleration

Question 14

What is acceleration upwards and downwards on earth equal to?

Answer 14

-9.81m/s²

9.81m/s²

Question 15

Do objects dropped and thrown reach the ground at the same time?

Answer 15

Yes. The vertical components become equal in both as the acceleration from gravity is equal

Question 16

What is the horizontal property of projected objects?

Answer 16

The horizontal component remains constant

Question 17

What is the vertical property of projected objects?

Answer 17

The vertical component of a projected object increases each time as gravity accelerates the vertical component

Question 18

What is thinking distance?

Answer 18

Thinking distance is the distance the car travels in the time between the driver noticing the hazard and applying the brakes

Question 19

What is braking distance?

Answer 19

Braking distance is the distance taken to stop once the brakes are applied

Question 20

What is the equation for stopping distance (simple)?

Answer 20

Stopping Distance = Thinking Distance + Braking Distance

Question 21

What factors affect thinking distance?

Answer 21

Drugs
Alchohol
Speed
People in the car

Question 22

What factors affect braking distance?

Answer 22

Tyre Tread
Speed
Ice
Road Surface
People in the car

Question 23

What is the formula for car stopping distance?

Answer 23

s = ut₀ + u² / 2a

t₀ is thinking time

Question 24

What is the relationship between stopping distance and initial velocity?

Answer 24

Distance is directly proportional to u²

Question 25

How do you estimate instantaneous speed?

Answer 25

Take the gradient of the tangent at a given point on a distance-time graph

Question 26

How do you estimate instantaneous acceleration?

Answer 26

Take the gradient of the tangent at a given point on a speed-time graph

Question 27

What are the two forces acting on a body when it falls through air on earth?

Answer 27

Weight Drag (Air)

Question 28

When is drag force in free-fall not ignored?

Answer 28

The body’s mass is very small in relation to surface area A body is falling at a considerable velocity

Question 29

What is the relationship between gravitational field strength and radius?

Answer 29

Gravitational field strength is inversely proportional to radius squared

Question 30

What are the methods of determining 'g'?

Answer 30

Light gates Stop watch Second method easier, but less accurate. Light gates are better

Question 31

What is the method for investigating terminal velocity?

Answer 31

Wrap elastic bands around tube of viscous liquid at intervals measured by rulers Drop ball and record time to reach each band Repeat 4 times and use magnet to remove ball

Question 32

What is the method for investigating initial speed and stopping distance?

Answer 32

Vehicle modelled by block Glue interruptor card to side of block so time for width of card to pass through gate Set up light gate to record average starting velocity ahead of block Push block and record average stopping distance

Question 32

How can the terminal velocity investigation be improved?

Answer 32

Taller tubes allow longer terminal velocity Larger intervals reduce percentage uncertainty

Question 33

What is the formula of the stopping distance investigation?

Answer 33

1/2 m v² = Fd v² is directly proportional to d

Question 34

How to make stopping distance investigation fair?

Answer 34

The surface the block is pushed on and block material should stay constant so variation of frictional force is minimal