A particle is thrown upwards from ground. It experiences a constant resistance force which can produce a retardation of `2 ms^-2.` The ratio of time of ascent to time of descent is (`g = 10 ms^-2`)

Options

A. `1 : 1`
B. `sqrt(2/3)`
C. `2/3`
D. `sqrt(3/2)`

Answer

B

Explanation

Retardation during upward motion
`a_1=10+2`
`=12m//s^2`

Acceleration during upward motion,
`a_2=10-2=8m//s^2`
`t=sqrt((2s)/a)`
or `tprop1/sqrta`
`:. (t_1)/(t_2)=sqrt((a_2)/(a_1))=sqrt(8/12)=sqrt(2/3)`