The number of significant figures in the measurement of a length 0.079000 m is

The acceleration of a vertically projected body at its highest reaching position is

A player can throw a ball to a maximum horizontal distance of 80 m . If he throws the ball vertically with the same velocity, then the maximum height reached by the ball is

If a man of mass 50 kg is in a lift moving down with an acceleration equal to acceleration due to gravity, then the apparent weight of the man is