Question

A ball is thrown is vertically upwards with a velocity of 20m/s . Find the time of flight ,neglecting the air resistance (g= 10m/s^2)

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:

time is 4 seconds .

Explanation:

given

u = 20 m/s , v = 0 m/s

time of flight is nothing but the time

g = 10 m/s^2

v = u + at

now in further caluclation we get time = 2 sec

time of flight = ascent + desent

2 sec + 2 sec = 4 sec .