its D
i hope this helps to future test takers. i took the test and had to retake it because their wasn't an answer
Answer:
a chemical reaction where electrons mix.
Explanation:
A nuclear reaction is when atomic nuclei combine, forming a new chemical element
A chemical reaction occurs when electrons from the last layer of atoms mix, forming molecules that have the same chemical elements as the reactants.
According to these definitions
C + 2 S → CS2
in a chemical reaction where electrons mix.
Answer:22537.92 J
Explanation:
Given
mass of karen 
Distance covered by Karen =69.6 m
acceleration due to gravity=9.8
inclination
vertically karen move

h=39.72 m
Work done by escalator on karen is equal to change in potential energy of karen


Answer:
0.71 J
Explanation:
320 g = 0.32 kg
According to law of energy conservation, the energy loss to external environment (air, ground) can be credited to the change in mechanical energy of the ball.
As the ball was dropped at H = 2 m above the ground then later reaches its maximum height at h = 1.2m, tts instant speed at those 2 points must be 0. So the kinetic energy at those points are 0 as well. The change in mechanical energy is the change in potential energy.
Let g = 9.81 m/s2

Since 1.8J of 2.51 J is due to work by air resistance, the rest of the energy (2.51 - 1.8 = 0.71 J) is would go to heating in the ground and ball when it bounces.