Motion (M3)

Question 1

Terminal velocity cake case practical

Answer 1

• Set up ruler 1m above ground
• Drop case from 1m up to 2m in 10cm increments
• measure time for each drop 3 times
• calculate v of each drop with mean time
• plot graph of average velocity against height
• plateu at terminal v

Question 2

Finding terminal velocity practical

Answer 2

• Drop a ball bearing into a tube of glycerine with a mark every 2 cm
• measure time between each marker 3 times
• calculate velocity between each point
• Table of distance, cumulative time, velocity
• human error if not measured correctly
• measure at eye level
• don’t touch the liquid

Question 3

Average speed

Answer 3

Distance travelled / time taken
dx/dt
Unit = ms^-1

Question 4

Instantaneous speed

Answer 4

Speed over very short interval
Tangent on a distance time graph
Unit = ms^-1

Question 5

Distance

Answer 5

Speed X time
Area under speed-time graph
Amount of ground an object has covered during movement

Question 6

Displacement

Answer 6

Velocity X time
Area under a velocity-time graph
How far out of place an object is

Question 7

Acceleration

Answer 7

Change in velocity / time taken
Gradient of a velocity-time graph
Rate of change of velocity

Question 8

Gradient of a velocity-time graph

Answer 8

Acceleration

Question 9

Gradient of a distance-time graph

Answer 9

Speed

Question 10

Gradient of a displacement-time graph

Answer 10

Velocity

Question 11

Area under a velocity-time graph

Answer 11

Displacement

Question 12

Area under a speed-time graph

Answer 12

Distance

Question 13

Thinking distance

Answer 13

The distance travelled between when you see a hazard and when you hit the brake

Question 14

Braking distance

Answer 14

The distance travelled between when you hit the brakes and when the vehicle stops

Question 15

Stopping distance

Answer 15

The total of the thinking distance and braking distance

Question 16

Newton’s first law

Answer 16

A body will remain at rest or continue to move with constant velocity unless acted upon by an external resultant force

Question 17

Newton’s second law

Answer 17

The rate of change of momentum of an object is directly proportional to the resultant force and takes place in the direction of the force

Question 18

Newton’s third law

Answer 18

When two objects interact, each exerts an equal but opposite force in each other during the intersction

Question 19

Mass

Answer 19

The amount of matter an object has.
Base quantity measured in kg

Question 20

Inertia

Answer 20

The natural tenancy of objects to resist change in their state of motion. The more mass an object has, the greater its inertia.

Question 21

Electromagnet and trapdoor method

Answer 21

Electromagnet holds a small metal ball
Current is switched off, a timer is triggered, electromagnet demagnetises and ball falls
Hits the trapdoor and breaks circuit, stopping the timer
s=ut + 1/2 at^2 with u = 0
Graph of height against time squared
Gradient = 1/2 g