Question

8.Driver of a three wheeler moving with a speed of 36km/h sees a child standing in the middle of the

road and brings his vehicles to rest in 4s just in time to save the child.What is the average retarding force

on the vehicle? The mass of the three wheeler is 400kg and mass of the driver is 65kg.ac​

Answer 1

The driver of a three wheeler moving with a speed of 36km/h sees a child standing in the middle of the road and brings his vehicle to rest in 4 s just in time to save the child What is the average retarding force on the vechicle ? The mass of three wheeler is 400 kg and mass of the driver is 65 kg .

Answer 2

✬Given✬

• Initial Speed u = 36km/h,u = 10m/sec
• Final speed v = 0 m/sec
• Time = 4 sec
• Mass of the three wheeler m = 400 kg
• Mass of the driver = 65 kg

★ To find ★

Retarding Force on the vehicle?

† Solution †

Total mass = 400+65

= 465 Kg

Using the first law of motion

v = u + at

➫ a = $\frac{v-u}{t}$

➫ a = $\frac{0-10}{4}$

➫ a = - 2.5 m/s²

Note = Negative sign shows that the velocity is decreasing.

Using the second law of motion

F = ma

➫ F = 465×(-2.5)

➫ -1162.5 Ans

Note = Here, negative sign shows that the force is acting again the direction of motion..