A ladder 5m long is leaning against a wall. The bottom of ladder is pulled along the ground, away from the wall, at the rate of `2cm//sec`. How fast is its height on the wall is decreasing when the foot of ladder is 4m away from the wall.

Sand is pouring from a pipe at the rate of 12 cm^3// s. The falling sand from a cone on the ground in such a way that the height of the cone is always one-sixth of the radius of the base. How fast is the height of the sand cone increasing when the height is 4 cm.

A ball is thrown vertically upwards from the ground with a velocity of 24.5 m/s . If g=9.8 m/s^2 , then the ball will be at a height of 29.4 metres from the ground after time