A rocket travels at 500m/s two minutes after its take-off. If it was initially stationary, calculate its acceleration. If the rocket has a mass of 1800kg, what force is required to give it an acceleration of 2m/s^2?
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a) Acceleration is the rate of change of velocity of an object
In this case, the equation that we will use to calculate it is
a = (v - u )/ t
where v is the rocket's final speed, u is its initial speed, and t is the time taken
Note: units of measurement
a: measured in m/s^2
v/u: measured in m/s
t: measured in s
Putting the given values into this equation, we find that
acceleration = (500 - 0)m/s / (2x60)s = 4.17 m/s^2 (2dp)
- Hints: the initial speed of the rocket was 0 m/s at it was stationary to begin with, and we multiply 2 by sixty as we must convert time values from minutes into seconds.
- I have included units in the calculation above- you dont need to do this at every stage of calculation but make sure you include units when giving a final answer!
b) We can work out the second part of this question using Newtons's second law of motion F = m x a
F = 1800 x 2 = 3600 N ( or 3600 kgm/s^2)
This law explains that the force (F) acting on an object is equal to the mass (m) of an object times its acceleration (a)
