The driver of a three-wheeler moving with a speed of 36 km/h brings his vehicle to rest in 4.0 s. Wh

Question

The driver of a three-wheeler moving with a speed of 36 km/h brings his vehicle to rest in 4.0 s. What is the magnitude of the average retarding force on the vehicle? The mass of the three-wheeler is 400 kg and the mass of the driver is 65 kg.

Professor PC Thomas Classes · Answer

Initial speed $u = 36$ km/h $= 10$ m/s. Final speed $v = 0$. Acceleration $a = \frac{0 - 10}{4} = -2.5$ m/s². Total mass $m = 400 + 65 = 465$ kg. Force $F = ma = 465 	imes (-2.5) = -1162.5$ N. The magnitude is 1162.5 N.