Question

A ball is thrown up with a velocity of 20 ms .What is the time of flight, neglecting air resistance?​

Answer 1

Answer:

Using kinematic equation, v = u + a× t, when ball reaches to top of its trajectory, it's velocity becomes zero. Ball is thrown against gravity of earth, therefore a = - g, u = 20 m/s, we can find time of ascend as

0 =20 - 10 × t

20 = 10 × t

t = 20/10 = 2 sec

Time of ascend is same as time of descend = 2 sec.

Time of flight = time of ascend + time of descend

Therefore time of flight = 4 sec.

Answer 2

Answer:

Solution: As the ball is thrown upward, the final velocity will be zero. Therefore, the total time of flight is 4 seconds

EXPLAIN:4 SECONDS IN ANS