Question

a stone is thrown vertically upwards it reached the maximum height in 30 s calculate the initial velocity of stone​

Answer 1

Answer:

Initial Velocity u=40

Fianl velocity v=0

Height, s=?

By third equation of motion

v

2

−u

2

=2gs

0−40

2

=−2×10×s

s=

20

160

⇒s=80m/sToatl distance travelled by stone = upward distance + downwars distance =2×s=160m

Total Diaplacement =0, Since the initial and final point is same.

Answer 2

____________________✨

Given :-

• time = 30s

• final velocity = 0m/s

• gravity = -10m/s^2 [ taken ]

To find :-

• initial velocity = ?

Formula :-

• v = u + gt _____ (i)

v - u = gt [ from equation ( i )

Solution :-

= v - u = gt

= 0m/s - u = -10m/s^2 × 30s

= -u = -300m/s

= u = 300m/s

_________________________

If you want to find the height :-

Formula :- v^2 - u^2 = 2gh

Solution :-

v^2 - u^2 = 2gh

0m/s^2 - ( 300m/s)^2 = 2 × ( -10m/s^2 ) × h

-90000m/s^2 = -20m/s^2 × h

h = 4500m