What force, in newton, your muscles need to apply to hold a mass of 5 kg in your hand ? State the assumption.

A ball is thrown vertically upwards. It goes to a height 20 m and then returns to the ground. Taking acceleration due to gravity g to be 10 m s^-2

find —

(a) the initial velocity of the ball

(b) the final velocity of the ball on reaching the ground and

(c) the total time of journey of the ball.

A ball is thrown vertically upwards. It returns 6 s later. Calculate (i) the greatest height reached by the ball, and (ii) the initial velocity of the ball. (Take g = 10 m s^-2 )

A pebble is thrown vertically upwards with a speed of 20 m s^-2. How high will it be after 2 s ? (Take g = 10 m s^-2)