Question
Find the average force needed to accelerate a car weighing 500kg from rest to 72km/h in a distance of 25m.
✓
Answer
m = 500kg, u = 0, v = 72km/h = 20m/s$\text{a}=\frac{\text{v}^2-\text{u}^2}{2\text{s}}$
$\Rightarrow\frac{400}{50}=8\text{m}/\text{sec}^2$
force needed to accelerate the car F = ma = 500 × 8 = 4000N
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