A car (mass = 860 kg) is at rest on the top of a tall hill. the car rolls down the hill and at the bottom, reaches a top speed of 19 m/s.
A) find the force of gravity on the car
560 x 9.8 = 5488 N
B) find the work done by gravity on the car
W = change in energy = kinetic energy
k= .5(560)(19^2) = 101,080 J
C) find the maximum height of the hill
Potential Gravity = M G H
101,080 = (560)(9.8)H
H = 18.4 M
In reality, the height of the hill is 23 m tall.
d0 find the % of total energy that was lost due to friction
I am so lost on this part.
To find the percentage of total energy lost due to friction, we can compare the difference between the initial potential energy (when the car is at the top of the hill) and the final kinetic energy (when the car reaches the bottom of the hill) with the initial potential energy.
1. Calculate the initial potential energy:
Initial potential energy (PE0) = mass * gravity * height
PE0 = 860 kg * 9.8 m/s^2 * 23 m = 188,548 J
2. Calculate the final kinetic energy:
Final kinetic energy (KEf) = 0.5 * mass * velocity^2
KEf = 0.5 * 860 kg * 19 m/s^2 = 158,060 J
3. Calculate the energy lost due to friction:
Energy lost (ΔE) = PE0 - KEf
ΔE = 188,548 J - 158,060 J = 30,488 J
4. Calculate the percentage of energy lost:
Energy lost percentage = (Energy lost / PE0) * 100
Energy lost percentage = (30,488 J / 188,548 J) * 100 ≈ 16.15%
Therefore, approximately 16.15% of the total energy was lost due to friction.