Answer:
The force of friction.
Explanation:
Gravity keeps the car on the ground.
Motion Allows the car to move.
The force of speed doesnt make sense.
Friction would cause the car to stop moving.
210J
PE is mgh in this context.
The molecules of a solid vibrate faster so that they start spreading out to become a liquid. This energy makes them vibrate faster so the bonds between molecules can't interact all that well anymore creating more distance. The stronger the bonds between the molecules the higher the energy (temperature) has to be to get them away from each other. Hope I didn't confuse you too much!
Chan Hee can expect to observe about the samples after 16 days is that three-fourths of each sample will have undergone radioactive decay. The best answer is letter B.
