Hypothesis: The heavier the car the slower ( the more the mass the slower), the more weight(force) we added the faster. Experiment:

Materials: Trolley

Elastic cords for accelerating trolley

Rod for attaching elastic cord to trolley

Ticker-timer with power supply unit

Ticker-tape

Sellotape

Process:

1.Thread a length of ticker-tape through a ticker-timer and attach the end to a trolley.

2.Pull a trolley with a fixed force along a bench. Loop one end of the elastic cord around a rod attached to the trolley. Keep the force constant by making sure that the cord is always stretched by the same amount as the trolley moves. Practice doing this.

3.Choose and cut through a dot near to the start of the tape. Do this when the trolley is travelling quite slowly but the dots are far enough apart to clearly distinguish one from another.

4.Count five dot-to-dot spaces and cut the tape, through a dot, again. You have cut a ‘five tick-tape’..

5.Draw a horizontal line, as a time axis, on a piece of paper. Glue your tapes, vertically and 10 centimetres apart, so the bottom of each tape touches this axis. This 10 centimetres represents 1 second.

7.Draw a vertical axis anywhere to the left of the first tape. This is a velocity axis(it can be called cm).

8.Mark a scale, in centimetres per second, on your vertical axis. Each vertical centimetre on your axis represents 5 centimetres per second.

Work out the average acceleration of your trolley during the time between the two tapes. Acceleration is ‘rate of change of velocity’. It is equal to the change in velocity divided by the time. Average acceleration = change in velocity/time taken.