Question:
A heavy ball is suspended from the ceiling of a motor car through a light string. A transverse pulse travels at a speed of 60 $\mathrm{cm} / \mathrm{s}$ on the string when the car is at rest and $62 \mathrm{~cm} / \mathrm{s}$ when the car accelerates on a horizontal road. Find the acceleration of the car. Tale $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^{2}$.
Solution:
