A 3 kg object is lifted 4 m. What is the increase in gravitational potential energy? (g = 9.8 m/s^2)

A 3 kg object is lifted 4 m. What is the increase in gravitational potential energy? (g = 9.8 m/s^2)

• A. 88.2 J
• B. 117.6 J
• C. 156 J
• D. 178.6 J

Answer: (B)

When you lift an object in a uniform gravitational field, the increase in gravitational potential energy is ΔU = m g h, where m is mass, g is gravitational acceleration, and h is the height raised. For m = 3 kg, g = 9.8 m/s^2, and h = 4 m, ΔU = 3 × 9.8 × 4 = 117.6 J. So the height change raises the energy by 117.6 joules. The other numbers would come from different heights (or masses) and don’t match the 4 m rise.

When you lift an object in a uniform gravitational field, the increase in gravitational potential energy is ΔU = m g h, where m is mass, g is gravitational acceleration, and h is the height raised. For m = 3 kg, g = 9.8 m/s^2, and h = 4 m, ΔU = 3 × 9.8 × 4 = 117.6 J. So the height change raises the energy by 117.6 joules. The other numbers would come from different heights (or masses) and don’t match the 4 m rise.