Question # A body is thrown vertically upwards with an initial velocity ( { }^{6} u^{prime} ) reaches a maximum height in 6 s. The ratio of the distance travelled by the body in the first second to the seventh second is

# A body is thrown vertically upwards with an initial velocity ( { }^{6} u^{prime} ) reaches a maximum height in 6 s. The ratio of the distance travelled by the body in the first second to the seventh second is

1) 1: 1

2) 11: 1

3) 1: 2

4) 1: 11

Solution

Initial velocity ( u=g times t=9.8 times 6=58.8 mathrm{m} / mathrm{s} )

distance S1 travelled in first second is calculated using ( " S=u x t-(1 / 2) times g times t^{2} ", u operatorname{sing} u=58.8 m / s, ) and ( t=1 s )

( S_{1}=58.8 times 1-(1 / 2) times 9.8 times 1 times=53.9 mathrm{m} )

since the paticle reaches maximum height in ( 6 mathrm{s} ), at 7th second travel, its initial velocity is zero.

hence distance S7 travelled in 7 th second ( = ) ( (1 / 2) times 9.8 times 1 times 1=4.9 mathrm{m} )

hence the ratio ( S_{1} / S_{7}=53.9 / 4.9=11 )