A ball is thrown vertically upwards with an initial velcoity u reaches maximum height in 5 ~s . The ratio of distance travelled by the ball in the 2 nd and 7 th second is (assume, g=10 m / s ^2 )

Step-by-step solution

When ball is at maximum height, its velocity is zero. From first equation of motion, v=u-g t 0=u-10 5 u=50 ~m / s Distance travelled in n th second, s_n=u+ a 2 (2 n-1) Distance travelled in 2nd second is given as s₂=50- 10 2 (4-1)=50-15=35 ~m Distance travelled in 7th second is equal to distance travelled in 2nd second from highest point to vertically downward direction. s₇=s₂ ^ =0+ 10 2 (2 2-1)=15 ~m s₂ s₇ = s₂ s₂ ^ = 35 15 = 7 3 or 7: 23