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2. If a spring compresses under a force a short distance, but stores a very large amount of potential energy in the spring, what can be said about the spring?

A. The spring is made of soft materials
B. The kinetic energy of the force is impossible to determine
C. The stiffness of the spring, represented by the spring constant value, must be very high
D. The amount of potential energy stored in the spring has to be half of what the original energy was

3. According to the Law of Conservation of Energy, where does the kinetic energy of a car engine come from?

A. The heat of friction from the brakes
B. The potential energy due to the gravitational field
C. The kinetic energy of the person pushing the gas pedal
D. The potential energy stored into the chemical bonds of the gasoline

4. A loaded cannon is stationary. If the cannon fires a cannonball giving it a positive velocity, the cannon will recoil and roll back. What would the cannon having a negative velocity indicate about the total kinetic energy of the system?

A. The loaded kinetic energy did not transfer entirely to the cannonball, some had to go to the cannon.
B. The cannon produces its own kinetic energy to cause it to move
C. The law of Conservation of energy is not valid in this specific case
D. The explosion of the gunpowder is not an efficient method of energy transfer