Motion Test - 4...

A body is projected vertically upward with an initial velocity $$u$$. If acceleration due to gravity is $$g$$, the time for which it remains in air, is

Give an example of motion in which average speed is not zero, but the average velocity is zero.

A pebble is thrown vertically upwards with a speed of $$20\ ms^{-1}$$. How high will it be after $$2\ s$$? (Take $$g=10\ ms^{-2}$$)

A body is moving vertically upwards. Its velocity changes at a constant rate from $$50 m s^{-1}$$ to $$20 m s^{-1}$$ in 3 s. What is its acceleration ?

A body falls from the top of a building and reaches the ground $$2.5  s$$ later. How high is the building? (Take $$g=10  m  {s}^{-2}$$)

A pebble thrown vertically upwards with an initial velocity $$50 \ m s^{-1}$$ comes to a stop in 5 s. Find the retardation assuming displacement in upwards direction to be positive.

The velocity of an object increases at a constant rate from $$20 m s^{-1}$$ to $$50 m s^{-1}$$in 10 s. Find the acceleration.

A body is dropped from the top of a tower. It acquires a velocity of $$20\ ms^{-1}$$ on reaching the ground. Calculate the height of the tower. (Take $$g=10\ ms^{-2}$$)

A stone is dropped freely from the top of a tower and it reaches the ground in $$4\ s$$. Taking $$g=10\ ms^{-2}$$, calculate the height of the tower.

An object falling freely from rest reaches ground in $$2  s$$. If acceleration due to gravity is $$9.8  ms^{-2}$$, the velocity of object on reaching the ground will be