We can work out how far the rocket travels above the spectators' heads based on the following information? The rocket generates a force (F) of 20N, its mass (m) is 0.5kg and it travels for 2 seconds (t). To work out the distance travelled, we need to calculate the velocity and in order to do that we must first determine the acceleration.

F = ma
20 = 0.5 x a
a = 20/0.5
a = 40ms^-2

Now that we know the acceleration, let's work out the velocity:
a = v/t
40 = v/2
v = 40 x 2
v = 80ms^-1

Finally, we can use this information to work out the distance travelled:
v = s/t
80 = s/2
s = 80 x 2
s = 160m

So the distance travelled by the rocked is 160m — safely above the spectators' heads!

Roman candles 

Major funding for Rough Science was provided by the National Science Foundation. Corporate funding was provided by Subaru.

Copyright © 2002 The Open University and WETA.