15.

A 3.0 kg block is pushed 3.0 m at a constant velocity up a vertical wall by a constant force applied at an angle of 30.0� with the horizontal, as shown in the figure. The acceleration of gravity is 9.81 m/s2.
If the coefficient of kinetic friction between
the block and the wall is 0.30, find
a) the work done by the force on the block.
Answer in units of J.

b) the work done by gravity on the block.
Answer in units of J.

c) the magnitude of the normal force between the block and the wall.
Answer in units of N.

I DO NOT

a) 183.79

b) -88.29
c) 106.111

To find the answers to these questions, we need to analyze the different forces and their effects on the block.

a) The work done by the force on the block can be calculated using the equation:
Work = Force * Distance * cos(theta)

The force applied on the block can be found by resolving the given force into its horizontal component. The horizontal component of the force can be calculated using the equation:
Force_horizontal = Force_applied * cos(theta)

Given that the force applied is at an angle of 30 degrees with the horizontal and has a magnitude that needs to be determined, we can use trigonometry to find the horizontal component of the force:
Force_applied = (magnitude of Force) * cos(30 degrees)

Now we can calculate the work done by the force:
Work = (Force_horizontal) * Distance * cos(theta)
Work = (Force_applied * cos(theta)) * Distance * cos(theta)
Work = (Force_applied * cos^2(theta)) * Distance

b) The work done by gravity on the block can be calculated using the equation:
Work = Force * Distance * cos(theta)

The force of gravity acting on the block can be calculated using the equation:
Force_gravity = mass * acceleration due to gravity

Now we can calculate the work done by gravity:
Work = (Force_gravity) * Distance * cos(theta)
Work = (mass * acceleration due to gravity) * Distance * cos(theta)

c) The magnitude of the normal force between the block and the wall can be found by considering the equilibrium of forces in the vertical direction. The normal force balances out the force of gravity in the vertical direction.

When the block is moving at constant velocity, the vertical forces acting on the block are the force of gravity and the vertical component of the applied force. The vertical component of the applied force can be calculated using the equation:
Force_vertical = Force_applied * sin(theta)

To maintain constant velocity, the vertical component of the applied force should be equal in magnitude but opposite in direction to the force of gravity. Therefore, the normal force can be calculated by considering the equilibrium condition:
Normal force + Force_gravity = 0

Now that we have calculated the necessary formulas, we can substitute the given values into the equations to find the answers to the three questions.

I don't know the answer