Paper 3 Practs

Question 1

What techniques can you use to investigate motion?

Answer 1

• Light gates and data logger.
• Linear air track.
• Trap door, for free fall.
• Camera, using the frame to calculate time.

Question 2

What are the key features of a displacement time graph?

Answer 2

• Gradient is the Velocity.
• If gradient is curved, then the object is accelerating.
• Instantaneous velocity can be found by a tangent to the curve at a point.

Question 3

What are the Key Features Velocity-Time graphs?

Answer 3

• The gradient is the acceleration.
• Displacement is the area under the graph.
• ## A curve represents a changing acceleration.

Question 4

How can the factors effecting motion be investigated by a trolley?

Answer 4

Motion down a slope can be instigated to see the effect of the angle of the slope, mass of the trolley, shape of the trolley, or how friction effects the motion.

Question 5

How can a camera be used to measure the time taken for an object to travelled past a point?

Answer 5

Time taken = (Number of frames till trolley passes a point) / Frame rate of camera.

Question 6

How can you experimentally find the centre of mass?

Answer 6

• Hang an object free from a point, using a plumb line draw a line vertically down from this point.
• Repeat this hanging the object from a different point.
• Where the lines overlap is the centre of mass.

Question 7

Describe a practical that can be used to measure terminal velocity.

Answer 7

• Get a long thin glass tube, make marks up the tube at fixed distances.
• Put a liquid in the glass tube.
• Drop a ball bearing down the tube, and record the time when the ball passes each mark.
• Work out the velocity between each mark.
• You should find the ball increases in velocity until it comes constant at its terminal velocity.