Answer:
Economic activity is the activity of making, providing, purchasing, or selling goods or services.
To convert 3 miles per hour into m/s, first we have to convert miles in to meter and then hour in to second.
As 
and
Therefore,
Answer:
C. The sum remains the same.
Explanation:
The sum of the kinetic and potential energy remains the same as the all rolls from point A to E.
We know this based on the law of conservation of energy that is in play within the system.
The law of conservation of energy states that "energy is neither created nor destroyed within a system but transformed from one form to another".
- At the top of the potential energy is maximum
- As the ball rolls down, the potential energy is converted to kinetic energy.
- Potential energy is due to the position of a body
- Kinetic energy is due to the the motion of the body
The Answer is B. Isotopes
