A body of mass 5kg starts from the origin with an initial velocity of `barU= (30i+40j)m//s`. A constant force of `F= (-hati - 5 hatj)N` acts on the body . Find the time in which they- component of the velocity becomes zero .

Explanation

`baru= 30i + 40 j` ....... (1)
` u=u_(x) hati + u_(y) hatj`........ (2)
`F= - hati - 5hatj` ........ (3)
` F= F_(x) hati + F_y hatj` ........ (4)
comparing (1) and (2), (3) and (4)
we have
`u_y = 40 m//s , F_y =-5N`
`F_y = ma_y , a_y = -1 m//s^(2)`
`v_y = u_y + a_y xx 1 , 0 = 40 -1 xx t , t = 40` sec