Question

A man throws balls into the air one after the other, throwing one when other is at the highest point. How high the balls rise if he throws twice a second?

• A. 2.45m
• B. 1.25m
• C. 19.6m
• D. 4.9m

Answer 1

Answer: (B)

1.25m

If he throw 2 balls a sec then time talen by ball to reach highest point is 0.5 sec. Then $0=u-10.\frac{1}{2}$

Gives $u=5m/s$. Now $S=ut+\frac{1}{2}a{t}^2$

$S=5\ast \frac{1}{2}/2-\frac{1}{2}\ast 10\ast \frac{1}{2^2}$

$S=1.25m$.