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 13 (`g = 10 ms^-2`)

Options

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

Answer

B

Explanation

`.vuarr underset(2m//s^(2))(darr)overset(*)(darr)gm//s^(2)" "._(v)darr darr g m//s^(2)uarr 2m//s^(2)`
`:.` time of ascent `=sqrt((2h)/(g+2))`
time of descent `=sqrt((2h)/(g-2))`
`:. T_(a)/t_(d)=sqrt(8/12)=sqrt(2/3)`