Answer:
Mechanical energy
Explanation:
A car changes chemical energy from fuel into thermal energy and mechanical energy.
Mechanical energy can be defined as the type of energy that is possessed by an object due to its motion or position. Mechanical energy is the sum of potential energy and kinetic energy, that is, the sum of energy in motion and stored energy. Examples of mechanical energy includes driving a car, riding a bicycle, listening to music etc.
Types of mechanical energy
1. Motion energy (kinetic energy)
2. Stored energy(potential energy)
Mechanical energy = Kinetic energy + Potential energy
Explanation:
Given that,
Bill is riding his bicycle at 5 m/s eastward: and Carlos is driving his car at 15 m/s westward.
Taking eastward as positive direction, we have:
is the velocity of Bill with respect to Amy (which is stationary)
is the velocity of Carlos with respect to Amy.
Bill is moving 5 m/s eastward compared to Amy at rest, so the velocity of Bill's reference frame is

Therefore, Carlos velocity in Bill's reference frame will be

So, the magnitude is 20 m/s and the direction is westward (negative sign).