Speed and velocity refer to the motion of an object. Distance-time and velocity-time graphs can be a useful way of analysing motion.

Part of

There are different ways to investigate the acceleration of an object down a ramp. In this practical activity, it is important to:

- make and record measurements of length and time accurately
- use appropriate apparatus and methods to measure motion

To investigate the acceleration of an object on an angled ramp.

- Set up a ramp balanced on a wooden block at one end. Mark out 30 cm at the end of the ramp. Avoid making the ramp too steep, as this will cause the trolley to roll too quickly, which could make measuring difficult.
- Practise recording the time it takes for the trolley to travel the length of the ramp. To do this, release the trolley from the top of the ramp, start the stop clock and record the time taken for the trolley to move the whole distance of the ramp.
- Repeat this twice more and record all results in a table similar to the one below. Then calculate the mean time and record this also. Remember that these are practise results.
- Next, record the time it takes for the trolley to travel the final section of the ramp. To do this, release the trolley from the top of the ramp again but this time start the stop clock when the trolley reaches the last 30 cm of the ramp.
- Record the time it takes for the trolley to travel the last 30 cm of the ramp in a table like the one shown below. These are your final results.
- Repeat this twice more, and record a mean time for the trolley to travel the last 30 cm of the ramp.
- Calculate the speed of the trolley when it was descending the last 30 cm of the ramp using the equation: speed (m/s) = distance (m) ÷ time (s). Remember to first convert 30 cm into metres by dividing it by 100 (there are 100 cm in 1 m).

It is important to record results in a suitable table, like the one below:

Run 1 (s) | Run 2 (s) | Run 3 (s) | Mean (s) | Overall speed (m/s) |
---|---|---|---|---|

Use the result from above as the final speed and take the initial speed of the trolley as 0 m/s. Calculate the acceleration of the trolley when descending the entire length of the ramp using acceleration (m/s^{2}) = change in speed (m/s) ÷ time taken (s). Remember that the change in speed is from 0 m/s to the calculated result.

- Acceleration depends on speed and time. What happens if the trolley takes a shorter time to travel the length of the ramp?
- What would happen if the angle of the ramp was different?

Hazard | Consequence | Control measures |
---|---|---|

Trolley falling | Injury to feet | Keep feet well away from end of ramp |