Four marbles are dropped from the top of a tower one after the other with an interval of one second. The first one reaches the ground after 4 seconds . When the first one reaches the ground the distance between the first and second, the second and third and the third and forth will be respectively

Options

A. 35, 25 and 15m
B. 30, 20 and 10mS
C. 20, 10 and 5m
D. 40, 30 and 20m

Explanation

For first marble,` h_(1)=(1)/(2)gxx16=8g`

For second marble, `h_(2)=(1)/(2)gxx9=4.5Omega`
For third marble, `h_(3)=(1)/(2)gxx4=2g`
For fourth marble, `h_(4)=(1)/(2)gxx1=0.5g`
`:.h_(1)-h_(2)=8g-4.5g=3.5g=35m`.
`:.h_(2)-h_(3)=4.5g-2g=2.5g=25m` and
`:.h_(3)-h_(4)=2g-0.5g=1.5g=15m`.