Question

a ball is thrown vertically upwards with a velocity of 40m/s find the time of ascend of the ball

Answer 1

u=40m/s(upward)
v=0(at highest point)
g=10m/s(downward)
Use v=u+at
0=40-10t
t=4sec

Answer 2

Maximum Height (s)= u²/2g

=40*40/2*10

=1600/20

=80m

v=0m/s

u=40m/s

s= -80m (- due to acceleration due to graviity)

v²= u² + 2as

0 = 1600 - 160a

160a = 1600

a= 10

Now

v=0m/s

v=0m/su=40m/s

v=0m/su=40m/ss= -80m (- due to acceleration due to gravity)

v=0m/su=40m/ss= -80m (- due to acceleration due to gravity)a= 10

v= u+ at

0 = 40 + (-10t)

[- due to acceleration due to gravity]

10t=40

t=4s

4 seconds