Question

. A 60 kg Chala is at the top of a slope, as shown in the figure. At the initial point A, he is 10 m vertically above point B. a) Setting the zero level for gravitational potential energy at B, find the gravitational potential energy of this system when Chala is at A and then at B. Finally, find the change in potential energy of the Chala-Earth system as Chala goes from point A to point B.​

Answer 1

• To find the gravitational potential energy of the Chala-Earth system at points A and B, we can use the formula:

Potential Energy (PE) = mass (m) × gravitational acceleration (g) × height (h)

• where: m = 60 kg (Chala's mass) g = 9.81 m/s² (gravitational acceleration on Earth)

For point A: h = 10 m (Chala is 10 m vertically above point B)

PE_A = 60 kg × 9.81 m/s² × 10 m = 5886 J (joules)

For point B: Since we set the zero level for gravitational potential energy at point B, the potential energy of Chala at point B is:

PE_B = 0 J (joules)

Now, let's find the change in gravitational potential energy as Chala goes from point A to point B:

∆PE = PE_B - PE_A = 0 J - 5886 J = -5886 J

The change in potential energy of the Chala-Earth system as Chala goes from point A to point B is -5886 J. The negative sign indicates that the gravitational potential energy has decreased.