Question

fast !!!!! explain me also !!!!

A ball is thrown vertically upwards from the ground. It crosses a point at height of 60 m twice at an interval of 4 s. The velocity with which ball will hit the ground is 40 m/s 20 m/s 30 m/s 15 m/s​

Answer 1

Explanation:

At the point 25m above it takes 4 sec. i.e., time of flight there is 4 s.

4=

g

2u

u=20m/s

at 25m height it has velocity 20m/s and it goes further height of

2g

u

2

=20m

Total max height =20+25=45m

Initial velocity.

45=

2g

u

2

u=30m/s