Question

How high will a 1.30-kg rock go from the point of release if thrown straight up by someone who does 80.0 J of work on it? Neglect air resistance.

Answer 1

Height it will go is 6.27 m

Explanation:

The work done on the stone is kinetic energy.

Kinetic energy = 80 J

We have

        Kinetic energy = 0.5 x Mass x Velocity²

        Mass = 1.30 kg

       80 = 0.5 x 1.30 x Velocity²

       Velocity = 11.09 m/s

We have equation of motion v² = u² + 2as

Initial velocity, u = 11.09 m/s  

Acceleration, a = -9.81 m/s²  

Final velocity, v = 0 m/s  

Substituting  

v² = u² + 2as

0² = 11.09² + 2 x -9.81 x s

s = 6.27 m  

Height it will go is 6.27 m