Answer to Question #92226 in Mechanics | Relativity for Isaac

Question

Calculate the force exerted on a car of mass 1 ton, that moved with velocity of 45km/hr on a rough road and it is brought to rest after 10 seconds

Answer 1

The Newton's second law states

$$F=ma$$

The acceleration of a car

$$a=\frac{\Delta v}{\Delta t}=\frac{0\:\rm{m/s}-45(\rm{1000\:m/3600\: s})}{10\:\rm{s}}=-1.25\:\rm{m/s^2}$$

Finally, the magnitude of the force exerted on a car

$$F=1000\:\rm{kg}\times 1.25\:\rm{m/s^2}=1250\:\rm{N}$$