Work Power Energy

To solve the problem, we need to understand the nature of the work done by the force of gravity on a satellite moving in a circular orbit around Earth.

1. Understanding the Concepts:

- Work Done by a Force: Work is defined as the force applied times the displacement in the direction of the force.
- Mathematically, where is the angle between force and displacement.
- Force of Gravity: Always acts towards the center of the Earth (radially inward).
- Satellite Movement: Satellite moves tangentially to its circular orbit, meaning its displacement at any instant is perpendicular to the gravitational force.

2. Analyze the Work Done by Gravity:

- Since the gravitational force acts towards the center and the satellite's instantaneous displacement is perpendicular (at 90°) to this force,
- The angle , and .
- Therefore, the work done by gravity over any segment of the circular path is:

3. Interpretation:

- Gravity changes the direction of the satellite's velocity but not its speed.
- Hence, it does no work on the satellite because the satellite's kinetic energy remains constant in uniform circular motion.

Final Answer:

The work done by the force of gravity on a satellite moving in a circular orbit around the Earth is zero.

To solve the problem, we first calculate the work done in joules and then convert it into millielectronvolts (meV).

1. Calculate Work Done in Joules:

Work done is given by: Where:
, , and .
Using :

2. Convert Joules to Millielectronvolts (meV):

- 1 electronvolt (eV) = joules (J)
- 1 millielectronvolt (meV) = eV

Convert joules to eV: Convert eV to meV:

Final Answer:

The work done to slide the crate is approximately 1.988 × 10²⁵ millielectronvolts (meV).