Question

Two balls are dropped from same height at $1$ second interval of time. The separation between the two balls after $4$ second of the drop of the $1^{\text{st }}$ ball is:

• A. 30 m
• B. 35 m
• C. 40 m
• D. 48 m

Answer 1

Answer: (B)

Motion of first ball $u=0,a=g,t=3$ sec.
We are consider that the $s$, is the distance covered by the
first ball in 4 seconds.
$s_1=ut+\frac{1}{2}g{t}^2$
$0+\frac{1}{2}\times 10\times (4{)}^2=80m$
Let $s$, be the distance covered by the second ball in $2$ seconds.
$s_2=0+\frac{1}{2}\times 10\times (3{)}^2=45m$
Separation between the two balls.
$S_1-S_2=80m-45m=35m$