The acceleration goes up.
Answer:
6 m/s
Explanation:
momentum= mass times velocity
120 = 20v
v = 120/20
The speed of the car at the bottom of the hill is obtained as, 
According the principle of conservation of energy, the total potential energy of the car will be converted to maximum kinetic energy when the car is at the bottom of the hill.

where;
- <em>v </em><em>is the speed of the car at the bottom of the hill</em>
- <em>h </em><em>is the height of the hill</em>
- <em>g </em><em>is acceleration due to gravity</em>
Thus, the speed of the car at the bottom of the hill is obtained as, 
Learn more about conservation mechanical energy here: brainly.com/question/332163
D.<span>Wave 3 resulted from constructive interference, and Wave 4 resulted from destructive interference.
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