Question

If you decide to launch a ball vertically to a friend located 45 m above you who can catch it. What is the minimum launch speed you can use?

• A. 4.5 m/s
• B. 1.50 m/s
• C. 45 m/s
• D. 29.7 m/s
• E. 90 m/s

Answer 1

The correct option is D 29.7 m/s

Given that,

Distance $s=45m$

Initial velocity $u=0$

We know that,

By using equation of motion

$v^2=u^2+2as$

$v^2=0+2\times 9.8\times 45$

$v^2=882m/s$

$v=29.7m/s$

Hence, the minimum speed is $29.7m/s$