Question

A race car has a mass of 833 kg. It accelerates uniformly from rest, and travels 48.9 m in 3.13 s.

Find the acceleration of the car.

Answer 1

A race car has a mass of $833\,\mathrm{kg}$. It accelerates uniformly from rest, and travels $48.9\,\mathrm{m}$ in 3.13 s. Find the acceleration of the car.

**Solution.**

$$m = 833\,\mathrm{kg},\ s = 48.9\,\mathrm{m},\ t = 3.13\,\mathrm{s};$$ $$a - ?$$

**Displacement is:**

$$s = v_0 t + \frac{a t^2}{2}.$$

$v_0 = 0$, because car accelerates from rest.

$$s = \frac{a t^2}{2};$$ $$a = \frac{2\,\mathrm{s}}{t^2};$$ $$a = \frac{2 \cdot 48.9}{3.13^2} = 9.98 \approx 10\,\left(\frac{\mathrm{m}}{\mathrm{s}^2}\right).$$

**Answer:** $a = 10\,\left(\frac{\mathrm{m}}{\mathrm{s}^2}\right)$.