Final answer:
The gain in potential energy when the weightlifter lifts a 200 kg mass to a height of 2.0 meters is 3922 Joules, calculated using the formula for gravitational potential energy which is PE = mgh.
Step-by-step explanation:
The student is asking about the gain in potential energy when a weightlifter lifts a mass of 200kg to a height of 2.0m. To calculate this, we use the formula for gravitational potential energy, which is PE = mgh, where m is mass, g is the acceleration due to gravity (approximately 9.81 m/s2), and h is the height the object is raised to. In this case, m = 200 kg, g = 9.81 m/s2, and h = 2 meters.
So the calculation would be PE = 200kg × 9.81 m/s2 × 2m. This results in a potential energy gain of 3922 Joules (J), which is the energy required to lift the weights to the given height.
The radius of the largest disc on the bar is provided, but it is not relevant to the calculation of potential energy in this context. This parameter might be useful for other kinds of problems, such as calculating the moment of inertia if the weights were to be rotated, but for the question of potential energy gain, only the mass, the acceleration due to gravity, and the height are necessary.