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 15 m
B. 30, 20 and 10 m
C. 20, 10 and 5 m
D. 40, 30 and 20 m

Answer

A

Explanation

For first marble , `h_1 = 1/2 g xx 16 = 8g`

`h_2 = 1/2 g xx 9 = 4.5 g`
`h_3 = 1/2g xx 4 = 2g`
`h_4 = 1/2 g xx 1 = 0.5g`
` therefore h_1 - h_2 = 8g - 4.5 = 3.5g = 35m`
`h_2 - h_3 = 4.5 g - 2g = 2.5g = 25m`
`h_3 - h_4 = 2g - 0.5g = 1.5g = 15m `