Answer:
No, not necessarily
Explanation:
If an object is moving with an acceleration that causes its speed to be reduced, there will be a moment in which it reaches v = 0, but this doesn't necessarily mean that the acceleration isn't acting anymore. If the object continues its movement with the same acceleration, it's velocity will become negative.
An example of an object that has zero velocity but non-zero acceleration:
If you throw an object in the air with a certain velocity, it will move vertically, reducing its velocity in a 9,8 
rate (which is the acceleration caused by gravity). At a certain point, the object will reach its maximum height, and will start to fall. In the exact moment that it reaches the maximum height, before it starts falling, its velocity is zero, but gravity is still acting on the object (this is the reason why it starts falling instead of just being stopped at that point). Therefore, at that point, the object has zero velocity but an acceleration of 9,8 .
Power = 
Delilah: 170J/30s = 5.66 W
Adam: 260J/20s = 13 W
Answer:
C. Takes heat in, does work, and loses energy heat.
Explanation:
Heat engine is a system makes use of thermal energy (heat) to in order to do mechanical work.
This occurs by converting the heat into mechanical energy. This energy is then used to do work.
The key characteristic of a heat engine is that the substance with which work is done by, goes from a higher temperature to a lower temperature.
Hence, it loses heat as it does work.
The SI unit for momentum is kg*(m/s)
Answer:
He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.
