Wrote the name and subject bad in the other post, sry::

Hello, this is the last question that I can't seem to be able to solve:

1. Jenny (75 kg) goes on a ski trip. She goes down a slope that's inclined at 15*. The drag coefficient of Jenny is 0.300, the surface of contact with air is 0.750 m^2 and the air density is 1,31 kg/m^3. The coefficient of kinetic friction between the skis and the snow is of 0,185.

Jennys speed according to her distance:

from 0 to 15m/s: between 0m and 50m
from 15 to 20 m/s: between 50m and 100m
constant 20m/s: 100m to 450m
from 20m/s to 0: 450m to 500m

Questions:

a) What is the Work done by the force of air resistance?

b) What is the Work done by the friction force between the skis and the snow?

c) What is the work of gravity?

d) What is the Power dissipated by the force of air resistance? What is the Power dissipated by the force of friction between the skis and the snow?

Thank you
No one has answered this question yet.

To solve this problem, we need to break it down into smaller parts and calculate the work done and power dissipated in each case. Let's go step by step:

a) The work done by the force of air resistance can be calculated using the formula:

Work = Force x Distance

The force of air resistance can be calculated using the formula:

Force = 0.5 x Drag Coefficient x Air Density x Area x Velocity^2

Plugging in the given values, we get:

Force = 0.5 x 0.300 x 1.31 kg/m^3 x 0.750 m^2 x (15 m/s)^2

Now we can calculate the work done:

Work = Force x Distance = (0.5 x 0.300 x 1.31 kg/m^3 x 0.750 m^2 x (15 m/s)^2) x 50 m

b) The work done by the friction force between the skis and the snow can be calculated using the formula:

Work = Force x Distance

The force of friction can be calculated using the formula:

Force = Friction Coefficient x Normal Force

The normal force can be calculated using the formula:

Normal Force = Mass x Gravity

Plugging in the given values, we get:

Normal Force = 75 kg x 9.8 m/s^2

Now we can calculate the force of friction:

Force = Friction Coefficient x Normal Force = 0.185 x (75 kg x 9.8 m/s^2)

Now we can calculate the work done:

Work = Force x Distance = (0.185 x (75 kg x 9.8 m/s^2)) x (100 m - 50 m)

c) The work of gravity can be calculated using the formula:

Work = Force x Distance

The force of gravity can be calculated using the formula:

Force = Mass x Gravity

Plugging in the given values, we get:

Force = 75 kg x 9.8 m/s^2

Now we can calculate the work done:

Work = Force x Distance = (75 kg x 9.8 m/s^2) x (500 m - 100 m)

d) Power is defined as the rate at which work is done, so it can be calculated using the formula:

Power = Work / Time

To calculate the power dissipated by the force of air resistance, we need to divide the work done by the time it takes for Jenny to cover the corresponding distance.

To calculate the power dissipated by the force of friction between the skis and the snow, we need to divide the work done by the time it takes for Jenny to cover the corresponding distance.

Remember to convert the distances given to the corresponding time intervals and use the formulas mentioned above to calculate the power dissipated.

I hope this helps you solve the problem!