Suppose a car approaches a hill at an initial speed of 118 km/h and no friction. The energy released during the climb is stored in the tires. When the car encounters friction, the energy is converted to thermal energy. The initial kinetic energ-y is approximately 108 J. The thermal energy is converted to heat. The car will then stop at 20.5 m above its starting height.
The work done by the car is constant, as the mass of the car is zero. The driver lets the vehicle coast up the hill, causing the change in energy to be the same as the initial one. The result is identical. The work done is the same, but the initial speed is higher than the final speed. The car’s work is equal to its mass multiplied by its initial speed squared.
Imagine a car approaching a hill at 120 km/h. The car will accelerate up the hill if the driver takes his foot off of the gas pedal. The car will use very little work due to friction. It will gain potential energ-y and lose kinetic energy. However, the change in kinetic energy will be less than half of the initial mass multiplied by the final speed.
Suppose a car approaches a hill at a constant speed of 120 km/h. The driver lets go of the gas pedal and the car coasts up the hill. The effort required is negligible. Thus, the initial speed is equivalent to the final speed. The initial speed of the driver does not lose any potential energy or kinetic energy. The change in kineticenergy is equal to half of the mass times the final velocity.
At the bottom of the hill, the car is at rest. The car has a constant speed. It is moving at a constant speed up the hill. Its initial kinetic energy is the same as its potential energy. Consequently, the car gains kinetic energy but loses potential energy. At the top of the hill, the car is at rest and loses kinetic energy. If it continues to roll, it will stop at a height of 20.5 m, which results in a corresponding increase in kinetic energy.
Suppose a car approaches a hill at an initial speed of 116 km/h and a final speed of 20 m. At this point, the driver depresses the gas pedal and lets the car coast up the hill. The work done at the top is equal to -324000J. If the car continues to move up the hill, it will generate more kinetic energy, which will be lost.
Imagine a car approaching a hill at 120 km/h. The driver then releases the gas pedal and the vehicle starts to climb the hill. The total work done by friction is very negligible, as the vehicle is not going up the hill. As the car progresses up the steep hill, it will gain potential energy and lose kinetic energy. Its total kinetic energy is 0J.
Suppose a car approaches a hill at a constant speed of 120 km/h. The driver releases the gas pedal, and the car coasts up the hill. The car will lose some kinetic energy, but will eventually gain potential energy. The car will eventually reach an average speed of zero, which is the desired result. It will continue to go up the hill. And then it will start rolling again.
Imagine a car approaching a hill at a speed of 116 km/h. The car approaches a hill at a constant speed. It stops at 20.5 m. The friction is therefore negligible. The car will gain kinetic energy if it coasts up the mountain.