A 1.0-kg object moving in a certain direction has a kinetic energy of 2.0 J. It hits a wall and comes back with half its original speed. What is the kinetic energy of this object at this point?
A) 2.0 J
B) 1.0 J
C) 0.50 J
D) 0.25 J
E) 4.0 J
Question 2
A rock is dropped from the top of a vertical cliff and takes 3.00 s to reach the ground below the cliff.
A second rock is thrown vertically from the cliff, and it takes this rock 2.00 s to reach the ground below the cliff from the time it is released. With what velocity was the second rock thrown, assuming no air resistance?
A) 4.76 m/s upward
B) 5.51 m/s downward
C) 12.3 m/s upward
D) 4.76 m/s downward
E) 12.3 m/s downward
Activation energy of a chemical reaction
Installation of Wall Drawing No. 681 C.
Winslow Homer, A Wall, Nassau.
Eye wall
The energy budget
Energy Transfer