The Driver of a three wheeler moving with a speed of 10 m per sec and stops a vehicle and bring it to rest in 4sec . What is the average retarding force acting on the vehicle . The mass of three wheeler is 400 kg and mass of drver is 65 kg .

AcademicPhysicsNCERTClass 9

Given: The Driver of a three-wheeler moving with a speed of 10 m per sec stops a vehicle and brings it to rest in 4sec. The mass of the three-wheeler is 400 kg and the mass of the driver is 65 kg.

To do: To find the average retarding force acting on the vehicle. 

Solution: 

As given, mass of the three-wheeler $m_1=400\ kg$

Mass of the driver $m_2=65\ kg$

Total mass $m=m_1+m_2=400+65=465\ kg$

Initial speed $u=10\ m/s$

Final speed $v=0$

Time $t=4\ s$

On using the first equation of motion, $v=u+at$

Or $0=10+a\times 4$     [Here $a$ is retardation]

Or $a=-\frac{10}{4}\ m/s^2$    [$-ve$ sign indicates retardation]

So, retarding force, $F=ma=465\ kg\times \frac{10}{4}\ m/s^2$

$=1162.5\ N$

raja
Updated on 10-Oct-2022 13:33:02

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