Question

18. A ball is thrown vertically down with velocity of 5 m/s. With what velocity should
another ball be thrown down after 2 seconds so that it can hit the 1" ball in next 2
second?
A. 40m/s
B. 10m/s
C. 15m/s
D. 20m/s​

Answer 1

Answer:

OKKKK

Explanation:

Answer 2

Explanation:

at 2s for first ball,

h = 5*2 + 0.5g*4 = > 30 meter.

and v = 5 + 10*2 = > 25 m/s

after further 2 seconds,

x= 25*2 + 0.5*g*4 = > 70 meter.

total distance it covered, => 70 + 30 => 100 meter.

for second ball,

100 = u*4 + 0.5g*16

4u = 100 – 80 = 20

4u = 20

u = 5 m/

Edit:

the second ball needs to cover that 100 m distance in 2 seconds not in 4.

Therefore,

100 = u*2 + 0.5*g*4

u = 40 m/s