Question

A ball is thrown upward. As it passes 5.0 m height it is traveling at 4.0 m/s up. What was its initial upward velocity? (a) 7.0 m/s ( b) 9.1 m/s (c) 10.7 m/s (d) 12.1 m/s (e) 14.6 m/s

Answer 1

Answer:

c) 10.7m/s

Explanation:

From the exercise we know that at 5m the ball  is traveling at 4m/s

To calculate its initial velocity we need to solve the following equation:

$v_{y}^{2}=v_{oy}^{2}+2g(y-y_{o})$

Since the initial height is 0

Solving for $v_{o}$

$v_{oy}=\sqrt{v_{y}^{2}-2gy}=\sqrt{(4m/s)^2-2(-9.8m/s^2)(5m)}=10.7m/s$