Question

A jet car can accelerate from stationary to 200ms-1 in 5.3 seconds. If its mass is 1200kg, calculate the average thrust it achieves during that time.

Answer 1

Explanation

• Momentum of the car changes from zero to some amount within a certain time.
• For a momentum change, there should be some kind of force/trust acting on it during that period.
• That average force/trust is calculated by, $\small F = \frac{\small\text{Final momentum}-\small\text{Initial momentum}}{\small \text{time}}$

Calculations

$\qquad \begin{aligned} \small \text{Thrust} &= \small \frac{mv-mu}{t}\\ &= \small \frac{m(v-u)}{t}\\ &= \small \frac{1200kg\times(200ms^{-1}-0ms^{-1})}{5.3s}\\ &= \small \bold{45283.02 \,N} \end{aligned}$