posted by James .
A man lifts a 1.0 kg stone vertically with his hand at a constant upward acceleration of 1.8m/2^2. what is the magnitude of the total force of the stone on the man's hand?
In Newtons downward?
The man's hand pushes the stone upward with force F = m a + m g (since F - Mg is the net force)
The stone pushes the man's hand downward with the same force. (Because of Newton's third law)