A ball is released from rest and rolls down an inclined plane, as shown in the following figure, requiring 4s to cover a distance of 100 cm along the plane:

Which one of the following is the correct value of angle `theta` that the plane makes with the horizontal? (g = 1000 `cm//s^(2)`)

Options

A. `theta=sin^(-1) (1//9.8)`
B. `theta=sin^(-1) (1//20)`
C. `theta=sin^(-1) (1//80)`
D. `theta=sin^(-1) (1//100)`

Answer

C

Explanation

`s=ut + 1//2 at^(2)`
`100=0 + 1//2 a x 4^(2)`
`a=200/8 = 12.5 cm//s^(2)`
acceleration `= g sin theta`
`or, g sin thea =12.5`
`or, sin theta = 12.5//1000=125//10000=1//80`
`theta= Sin^(-1) (1//80)`