Question

A body is thrown with speed 20 m/s vertically upwards,if will return to thrower's hand after a time $(g=10m/s^2)$

• A. 2 s
• B. 4 s
• C. 20 s
• D. Never

Answer 1

The correct option is B 4 s

Given that,

Initial velocity $u=20m/s$

Final velocity $v=0$

Now, from equation of motion

$v=u-gt$

$0=20-10t$

$t_1=\frac{20}{10}$

$t_1=2s$

Total time

$t=2t_1$

$t=2\times 2$

$t=4s$

Hence, the time is $4s$