Assertion (A): Force exerted by the ground on the man moves him forward.
Reason (R) : It is a reactional force,.

(A) : When a bicycle is in motion, the force of friction exerted by the ground on the two wheels is always in forward direction. (R ) : The frictional force only when the bodies are in contact.

Assertion(A) : The earth revolves around the sun an elliptical orbit Reasoning(R) : The sun alwaye attracts the earth with the same force

Assertion: A rocket moves forward by pushing the surrounding air backwards. Reason: It derives the necessary thrust to move forward according to Newton's third law of motion.

Assertion :- Work done by frictional force may be sometimes path independent. Reason :- Frictional force is a non - conservative force.

Assertion (A) : Work done in uniform circular motion is zero. Reason (R) : Force is always directed along displacement .

Assertion :- When a man climbs the rope friction force acts in downward direction. Reason :- Friction force opposes relative motion ot tendency of relative motion between two contact surfaces.

A roller of mass 500kg is attached by a light horizontal chain to a tractor of mass 500kg. Assume the force of friction exerted by the ground to be 1000N. If the system has a forward acceleration of 2ms^(-2) , calculate (i) the total force required for the motion and (ii) the tension in the chain.

Assertion : An external force is required to keep a body in motion. Reason : If the net external force is zero, a body at rest continues to remain at rest and a body in motion continues to move with a uniform velocity.

Assertion:- A man standing at rest on ground. Magnitude of force exerted by man on ground is equal to weight of man. Reason:- Earth attracts man by force mg hence by Newton's third law man also attracts earth by same force.

Assertion (A) : When a catalyst is added to a reaction mixture in equilibrium the amount of the products increases. Reason (R) : The forward reaction becomes faster on adding the catalyst.