Which scenario is an example of the transfer of thermal energy by radiation? A. You warm your feet in front of a fireplace.
B. A person uses a hot iron to remove wrinkles from a shirt,
C. The air in a hot-air balloon is heated by a gas burner
D. A cup heats up when you pour hot water into it.

help!!

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

Chemical energy is a form of energy. a. heat b. kinetic c. potential d. electromagnetic

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?