The final kinetic energy of the skateboarder after she freewheels and did work against friction on the flat section of the path is 4,600 J.
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Conservation of energy</h3>
The final kinetic energy of the stakeboarder is determined by applying the principle of conservation of energy as shown below;
ΔK.E = -W
K.Ef - K.Ei = -W
where;
- K.Ef is the final kinetic energy
- K.Ei is the initial kinetic energy
- W is work done
K.Ef = K.Ei - W
K.Ef = 5,000 J - 400 J
K.Ef = 4,600 J
Thus, the final kinetic energy of the skateboarder is 4,600 J.
Learn more about kinetic energy here: brainly.com/question/25959744
The law of reflection states that the angle of reflection is equal to the angle of Incidence .
Answer:
Part a)

Part b)

So this speed is independent of the mass of the rider
Explanation:
Part a)
By force equation on the rider at the position of the hump we can say

now we will have


now we have



Part b)
At the top of the loop if the minimum speed is required so that it remains in contact so we will have

at minimum speed




So this speed is independent of the mass of the rider
Answer:
The force would be the same in both cases - option C.
Explanation:
The change in momentum is known as an impulse. In the two cases under consideration, the change in momentum is the same, thus impulse for both cases is the same.
Impulse is the average force multiplied by time interval.
I = F(average)*ΔT. Where F(average) is the average force and ΔT is the time interval.
The average force in both cases is the same since the collision time is the same.
Thus option C is the correct answer.
For Mass
K.E = (1/2*mv^2)
Explanation:
Kinetic energy (KE) is equal to half of an object's mass (1/2*m) multiplied by the velocity squared. For example, if a an object with a mass of 10 kg (m = 10 kg) is moving at a velocity of 5 meters per second (v = 5 m/s), the kinetic energy is equal to 125 Joules, or (1/2 * 10 kg) * 5 m/s2.