A car of mass m starts from rest and acquires a velocity along east `upsilon = upsilonhati (upsilon gt 0)` in two seconds Assuming the car moves with unifrom acceleration the force exerted on the car is .A. `(mv)/(2)` eastward and is exerted by the car engineB. `(mv)/(2)` eastward and is due to the friction on the tyres exerted by the roadC. more than `(mv)/(2)` eastward exerted due to the engine and overcomes the friction of the roadD. `(mv)/(2)` exerted by the engine

A car of mass m starts from rest and acquires a velocity along east `u

1.	A car of mass m starts from rest and acquires a velocity along east `upsilon = upsilonhati (upsilon gt 0)` in two seconds Assuming the car moves with unifrom acceleration the force exerted on the car is .A. `(mv)/(2)` eastward and is exerted by the car engineB. `(mv)/(2)` eastward and is due to the friction on the tyres exerted by the roadC. more than `(mv)/(2)` eastward exerted due to the engine and overcomes the friction of the roadD. `(mv)/(2)` exerted by the engine
Answer» Correct Answer - B Given, mass of the car = m As car starts from rest, `u=0` Velocity acquired along east `=v_(i)` Duration `=t=2s` We known that, `v=u+at implies v hat(i)=0+a xx 2` `implies a=v/2 hat(i)` Force, `F=ma =(mv)/2 hat(i)` Hence, force acting on the car is `(mv)/2` towards east. As external force on the system is only driction hence, the force `(mv)/2` is by friction. Hence, force by engine is internal force.