A ball is thrown vertically upward with an initial velocity . . .

Question : A ball is thrown vertically upward with an initial velocity of 150 m/s. The ratio of velocity after 3s and 5s is [x+1]/x. The value of x is _________ [Take g=10 m/s²]

Doubt by Shruti

Solution :

Intial velocity (u) = 150 m/s acceleration (g) = - g Final velocity after 3sec v=u+at v=u-gt v=150-10(3) v=150-30 v=120

Final velcity after 5sec

v'=u+at v'=u-gt v'=150-10(5) v'=150-50 v'=100

Now

v/v'=[x+1]/x 120/100=[x+1]/x 12/10=[x+1]/x 6/5=[x+1]/x 6x=5x+5 6x-5x=5 x=5

Hence, the value of x is 5.