Question

1. A bali thrown up vertically returns to the thrower after 6s.lf acceleration of stone during its
n-ation is 10 m/s2.
Find (a) Velocity with which it was thrown up.
ta) Maximum height it reaches.​

Answer 1

Answer:

v= 0

u=?

t= 6 sec

a=10 m/s square

Use formula v= u+gt

For finding height use formula

v square = u square+2gh( in both g will be negative)we know g= 9.8 m/ s square

Answer 2

Answer:

Explanation:

The ball returns to the ground after 6 seconds.

Thus the time taken by the ball to reach to the maximum height (h) is 3 seconds i.e t=3 s

Let the velocity with which it is thrown up be  u

(a). For upward motion,                

v=u+at

∴     0=u+(−10)×3                  

⟹u=30  m/s      

(b). The maximum height reached by the ball

h=ut+  1 /2 at2

h=30×3+  1/2 (−10)×3  2

               

h=45 m  

(c). After 3 second, it starts to fall down.  

Let the distance by which it fall in 1 s   be   d

d=0+  1/2 at  2 ′        

where   t  =1 s

′

d=  1/2×10×(1)  2

=5 m  

∴ Its height above the ground, h  

′

=45−5=40 m  

Hence after 4 s, the ball is at a height of 40 m above the ground.