Question

What Is the kinetic Energy of an automobile weighing 1600kg when it travels
(a) 25.0 km/h (b) 50.0 km

Answer 1

Answer on Question #72940, Physics / Atomic and Nuclear Physics

Question. What is the kinetic energy of an automobile weighing $1600 \, kg$ when it travels (a) $25.0 \, km/h$ (b) $50.0 \, km/h$?

Given. $m = 1600 \, kg$; $v_1 = 25.0 \, km/hr \approx 6.94 \, m/s$; $v_2 = 50.0 \, km/hr \approx 13.89 \, m/s$.

Find. $KE_1, KE_2 - ?$

Solution.

According to the formula of the kinetic energy

$$KE = \frac{mv^2}{2},$$

we have

$$KE_1 = \frac{mv_1^2}{2} = \frac{1600 \cdot 6.94^2}{2} = 38530.88 \, J,$$ $$KE_2 = \frac{mv_2^2}{2} = \frac{1600 \cdot 13.89^2}{2} = 154345.68 \, J.$$

Answer. $KE_1 = 38530.88 \, J, KE_2 = 154345.68 \, J$.

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