Q.6. A man of mass 60 Kg is standing on the floor holding a stone weighing 40 N. What is the force with which the floor is pushing him up?

Sure, here's how to solve this problem:

Step 1: Identify the forces acting on the man. There are two forces acting on the man: the force of gravity pulling him down and the normal force (the force with which the floor is pushing him up).

Step 2: Calculate the force of gravity acting on the man. The force of gravity is given by the equation F = m*g, where m is the mass of the man and g is the acceleration due to gravity. Given that the man's mass is 60 kg and the acceleration due to gravity is approximately 9.8 m/s^2, the force of gravity acting on the man is 60 kg * 9.8 m/s^2 = 588 N.

Step 3: Calculate the force of gravity acting on the stone. The weight of the stone is given as 40 N. Weight is the force of gravity acting on an object, so the force of gravity acting on the stone is 40 N.

Step 4: Add the forces of gravity acting on the man and the stone to find the total force acting downwards. The total force acting downwards is 588 N (from the man) + 40 N (from the stone) = 628 N.

Step 5: According to Newton's third law, the force with which the floor is pushing the man up (the normal force) must be equal and opposite to the total force acting downwards. Therefore, the force with which the floor is pushing the man up is also 628 N.