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During the skateboard finals, Jonas encounters a 6 m long, 15◦ upward ramp. Jonas’s mass, including the skateboard, is 65 kg, and the coefficient of rolling friction between her wheels and the ramp is 0.025(b) Find the net mechanical energy at the top of the ramp. (c) With what speed must he start up the ramp to reach the top at 2.5 m s−1? (d) What percentage of his mechanical energy is lost to friction? (e) Jonas now runs forward with his skater at 2.0 m s−1 to the top of an arched skating ramp with a radius of curvature 5 m. The ramp is a very slippery slope. What is his (i) maximum normal force, and (ii) speed at the bottom of the ramp?Solve it and calculate the equation

Question

During the skateboard finals, Jonas encounters a 6 m long, 15◦ upward ramp. Jonas’s mass, including the skateboard, is 65 kg, and the coefficient of rolling friction between her wheels and the ramp is 0.025(b) Find the net mechanical energy at the top of the ramp. (c) With what speed must he start up the ramp to reach the top at 2.5 m s−1? (d) What percentage of his mechanical energy is lost to friction? (e) Jonas now runs forward with his skater at 2.0 m s−1 to the top of an arched skating ramp with a radius of curvature 5 m. The ramp is a very slippery slope. What is his (i) maximum normal force, and (ii) speed at the bottom of the ramp?Solve it and calculate the equation

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Solution

To solve this problem, we will break it down into several steps:

(a) Find the net mechanical energy at the top of the ramp: The net mechanical energy at the top of the ramp can be calculated using the formula:

Net mechanical energy = Potential energy + Kinetic energy

Potential energy can be calculated using the formula:

Potential energy = mass * gravity * height

In this case, the height of the ramp can be calculated using trigonometry:

Height = ramp length * sin(ramp angle)

Substituting the given values, we have:

Height = 6 m * sin(15°)

Next, we can calculate the potential energy:

Potential energy = 65 kg * 9.8 m/s^2 * Height

Kinetic energy can be calculated using the formula:

Kinetic energy = 0.5 * mass * velocity^2

Since Jonas is at the top of the ramp, his velocity is 0 m/s. Therefore, the kinetic energy is 0.

Finally, we can calculate the net mechanical energy:

Net mechanical energy = Potential energy + Kinetic energy

(b) Find the speed at which Jonas must start up the ramp to reach the top at 2.5 m/s: To find the required speed, we can use the conservation of mechanical energy. At the top of the ramp, the net mechanical energy is equal to the initial mechanical energy. Therefore, we can set the initial mechanical energy equal to the net mechanical energy calculated in part (a) and solve for the velocity:

Initial mechanical energy = Net mechanical energy

0.5 * mass * velocity^2 = Net mechanical energy

Solving for velocity, we have:

velocity = sqrt(2 * Net mechanical energy / mass)

Substituting the given values, we have:

velocity = sqrt(2 * Net mechanical energy / 65 kg)

(c) Calculate the percentage of mechanical energy lost to friction: To calculate the percentage of mechanical energy lost to friction, we need to find the mechanical energy lost due to friction. This can be calculated using the formula:

Mechanical energy lost = coefficient of rolling friction * mass * gravity * ramp length

Then, we can calculate the percentage of mechanical energy lost:

Percentage of mechanical energy lost = (Mechanical energy lost / Net mechanical energy) * 100

Substituting the given values, we have:

Mechanical energy lost = 0.025 * 65 kg * 9.8 m/s^2 * 6 m

Percentage of mechanical energy lost = (Mechanical energy lost / Net mechanical energy) * 100

(d) Calculate the maximum normal force and speed at the bottom of the arched skating ramp: To calculate the maximum normal force, we need to consider the forces acting on Jonas at the bottom of the ramp. The normal force is equal to the weight of Jonas and the skateboard, which can be calculated using the formula:

Normal force = mass * gravity

Substituting the given values, we have:

Normal force = 65 kg * 9.8 m/s^2

To calculate the speed at the bottom of the ramp, we can use the conservation of mechanical energy. The initial mechanical energy is equal to the net mechanical energy at the top of the ramp. Therefore, we can set the initial mechanical energy equal to the net mechanical energy and solve for the velocity:

Initial mechanical energy = Net mechanical energy

0.5 * mass * velocity^2 = Net mechanical energy

Solving for velocity, we have:

velocity = sqrt(2 * Net mechanical energy / mass)

Substituting the given values, we have:

velocity = sqrt(2 * Net mechanical energy / 65 kg)

(i) maximum normal force = 65 kg * 9.8 m/s^2 (ii) speed at the bottom of the ramp = sqrt(2 * Net mechanical energy / 65 kg)

By following these steps and substituting the given values, you can calculate the net mechanical energy, the required starting speed, the percentage of mechanical energy lost, the maximum normal force, and the speed at the bottom of the ramp.

This problem has been solved

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