Question

A car is moving with a uniform speed of 72 km/h. After applying brakes it stops after traveling 100 m distance. If its mass along with the passengers is 1000 kg, then the value of force due to the application of brakes will be in newton:

Answer 1

Explanation:
We know that,Force: The interaction which after applying on a body changes or try to change the state of rest or state of motion of the body is called force.Force (F)= Mass (m)× acceleration (a)Retardation: The force acting in the opposite direction to the motion of a body is called the retarding force. This force produces negative acceleration for the body which is called retardation or deacceleration.Retardation (a)=ForceMassThe equation of motion is given below:V=u+atV2=u2+2aSWhere V is final velocity, u is initial velocity, a is acceleration, t is time and S is distance.Given that:Mass (m)=1000 kgInitial velocity (u)=72 km/h=(72×1000)3600=20 m/sDistance (S)=100 mFinal velocity (V)=0 m/sWe know that car is stopped, which means the final velocity is 0.V2=u2+2aS0=202+2×a×100Acceleration (a)=−400200=−2 m/s2Force (F)=ma=1000×(−2)=−2000 NHence, the correct answer is –2000.