High School

To lift a 5 kg mass to a certain height, 245 J of energy is spent. To what height was the mass raised?

a) 10 m
b) 15 m
c) 20 m
d) 25 m

Answer :

The height to which a 5kg mass was raised using 245J of energy, assuming the gravitational acceleration is 9.8 m/s^2, is approximately 5 meters, which is not listed in the options.

The amount of energy spent to lift a mass can be calculated using the formula for gravitational potential energy, which is U = mgh, where U is the gravitational potential energy in joules (J), m is the mass in kilograms (kg), g is the acceleration due to gravity (9.8 m/s2 or approximately 10 m/s2 for simplification), and h is the height in meters (m) to which the mass is raised.

To find the height the mass was raised, we rearrange the formula to solve for h: h = U / (mg). Substituting the given values into the equation:

h = 245 J / (5 kg \u00d7 9.8 m/s2)
h = 245 J / (49 kg\u00b7m/s2)
h = 5 m

However, the options given do not include 5 m as an answer, thus there may be an error in the question, or it assumes a rounded acceleration due to gravity (g = 10 m/s2). If we use this rounded value for g, we find:

h = 245 J / (5 kg \u00d7 10 m/s2)
h = 245 J / (50 kg\u00b7m/s2)
h = 4.9 m

Since 4.9 m is not an option, the closest choice given the rounded gravitational acceleration would be option a) 5 m, which would correspond to the actual calculation when assuming g = 9.8 m/s2.