A car accelerates on a horizontal road due to the force exerted by
Friction force applied by road on the car act in the direction of the motion which is responsible to move the car.
A body of weight W1 is suspended from the ceiling of a room through a chain of weight W2. The ceiling pulls the chain by a force
Total weight of chain + block system is W1 +W2.
When a constant force is applied to a body, it moves with uniform
From Newton's second law of motion, F= m.a
if force is constant acceleration remains constant.
A particle is moving with a constant speed along a straight line path. A force is not required to
As the particle moves with constant speed in straight line its velocity is constant i.e accleration is zero. From Newton's second law of motion
F=m.a
Force required to keep moving with uniform velocity is zero.
A passenger in the bus finds that his suit-case suddenly starts sliding backwards. This means that the bus is :
This is due to inertia of motion.
The linear momentum of a particle is given by P = a + bt², where t is time and a & b are constants. The force acting on the body is directly proportional to :
Given momentum of the object is P = a + bt²;
Force is defined as rate of change of momentum F= dP/dt= 2bt. so Force is proportional to t.
A body of mass 1 kg moving on a smooth horizontal surface with velocity 5m/s is to be brought to rest in 5 sec. How much force need to be applied :
Force is defined as rate of change of momentum ie. F= dP/dt= change in momentum / time
Here Force = (mv-mu)/t= m(v-u)/t= 1 kg (0- 5)/ 5 = 1 N
The momentum of a particle is P = 2cos tˆi + 2sin t ˆj. What is the angle between the force F acting on the particle and the momentum P ?
Momentum of object is given as, P = 2cos tˆi + 2sin t ˆj ,
From Newtons Second law, F = dP/dt = -2 sin t î + 2 cos t ˆj.
Taking Dot product of P and F we get = -4 sint . cos t + 4 sint .cost =0 .
So, force and momentum are perpendicular to each other.
Passengers standing in a bus are thrown outwards when the bus takes a sudden turn. This happens because of :
Due to inertia of direction person inside the bus has a tendency to move in a straight line. In case of sudden turn body ties to maintain its linear motion.
A body moving with uniform velocity is stopped in 0.25 sec by applying a force of 200 N. What is the impulse :
Impulse is change in momentum so, J = F.dt = 200 × 0.25 =50 N-s