Force and Motion

Activity Sheet 2

Speed and Acceleration 1

[See 13.3 – sample layout plus graph illustrations]

1. Look at this graph showing how the speed of a runner changes during a race:

[See 13.3 - Insert graph showing slight delay before acceleration then a fast constant speed slowing after finish line at 100m Time for race 18s. Point where constant speed reached (8s 25m) labelled on graph]

a) How long was the distance of the race?
b) Did the runner stop at the finish line?
c) For how many seconds did the runner move at a constant speed?
d) How many metres did the runner cover at this constant speed?
e) Use the time from (c) and the distance from (d) to calculate the constant speed.
f) What was the average speed for the whole race?

2. This graph shows the speed of a second runner in the same race:

[See 13.3 - Insert similar graph but with much better acceleration at start. Doesn’t achieve same speed as other runner, but wins. Time for race 17s. Point where constant speed reached (5s 25m) labelled on graph]

a) Which of the two runners won the race?
b) What was the average speed of this runner for the whole race?
c) From the time that this runner moved at constant speed and the distance covered at constant speed, calculate the constant speed of this runner.
d) Which runner reached the highest speed during the race?
e) If you were advising the losing runner, what would you tell them to improve?

3. This data was recorded for a car. Use graph paper to plot a graph of distance travelled in metres against time in seconds.

Distance from the start in metres	Time taken in seconds
0	0
15	5
60	10
130	15
250	20
375	25
500	30

a) When was the car travelling at constant speed?
b) When was it accelerating?
c) What was the average speed for the whole 30 seconds?