When a balloon is rubbed with a wool cloth, e<span>lectrons move from the atoms in the balloon to the atoms in the cloth, causing the cloth to have a negative charge. Therefore, the answer is B. Before they were rubbed together, they both had balanced charges. However, after rubbing them, the wool is left with the positive charge, and the balloon with the negative. This causes the atoms in the cloth to flow to the balloon, leaving the cloth with a negative charge.</span>
1. U = Q + W
U = -500 + 1000
U = 500 J
2. The first law of thermodynamic is about the law of conservation of energy where energy in should be equal to energy out.
3. It is the windmill that does not transform energy from heat to mechanical instead it is the transforms the opposite.
4. In a heat engine, work is used to transfer thermal energy from a hot reservoir to a cold one.
5. 5.00 × 10^4 J - 2.00 × 10^4 J = 3.00 × 10^4 J
6. To increase the work done, we raise the temperature of the cold reservoir.
