How much work would be needed to lift the ball from the 2-m shelf to the 5-m shelf, and how much potential energy would it have on the 5-m shelf?

a) 2.94 N

b) 4.90 N

Explanation:

Let us assume that the weight of the ball is 0.98 N

Solution:

a) An object’s gravitational potential energy depends on two factors which are height and its weight (or mass). The equation for gravitational potential energy (PE) is given as:  

Potential energy = weight (w) * height (h)

PE = wh

Potential energy at 2 m shelf = weight * height = 0.98 N * 2 m = 1.96 N

Potential energy at 5 m shelf = weight * height = 0.98 N * 5 m = 4.90 N

The work needed to lift the ball from the 2-m shelf to the 5-m shelf = Potential energy at 5 m shelf - Potential energy at 2 m shelf

The work needed to lift the ball from the 2-m shelf to the 5-m shelf = 4.90 N - 1.96 N = 2.94 N

b) Potential energy at 5 m shelf = weight * height = 0.98 N * 5 m = 4.90 N

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