Question

An object is thrown vertically upward with a speed of $30m/s$. The velocity of the object half a second before it reaches the maximum height is

• A. $4.9m/s$
• B. $9.8m/s$
• C. $19.6m/s$
• D. $25.1m/s$

Answer 1

The correct option is A $4.9m/s$

Velocity half second before maximum height $=$ Velocity half second after maximum height (Return journey)
For downward journey :
Initial velocity $u=0m/s$
We have $g=9.8m/s^2$
Time $t=\frac{1}{2}s$
Thus velocity after half second $v=u+gt$
$v=0+9.8\times \frac{1}{2}=4.9m/s$