A 3.00 10^2 N force is pulling an 80.0 kg refrigerator across a horizontal surface. The force acts at an angle of 18.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 8.00 m
a) Find the work done by the pulling force
(b) Find the work done by the kinetic frictional force.
To find the work done by the pulling force and the kinetic frictional force, we need to use the formulas for work.
(a) The work done by a force is given by the equation:
Work = Force * Distance * cos(theta)
where Force is the magnitude of the force, Distance is the distance moved, and theta is the angle between the force and the direction of motion.
In this case, the magnitude of the force is 3.00 * 10^2 N, the distance moved is 8.00 m, and the angle theta is 18.0°. Therefore, the equation becomes:
Work = (3.00 * 10^2) * (8.00) * cos(18.0°)
To calculate this, make sure your calculator is set to degree mode, then calculate the cosine of 18.0° and multiply it by the other numbers.
(b) The work done by the kinetic frictional force is given by the equation:
Work = Force of friction * Distance
where Force of friction is the product of the coefficient of kinetic friction and the normal force.
In this case, the coefficient of kinetic friction is 0.200. To find the normal force, we need to consider the vertical forces. The weight of the refrigerator is given by:
Weight = mass * gravity
where mass is 80.0 kg and gravity is 9.8 m/s^2.
Therefore, the normal force is equal to the weight of the refrigerator, since the refrigerator is not accelerating vertically. Hence, the normal force is calculated as:
Normal force = mass * gravity
Once you have the normal force, you can calculate the force of friction using the equation:
Force of friction = coefficient of kinetic friction * normal force
Finally, you can calculate the work done by the kinetic frictional force using the formula:
Work = Force of friction * Distance
Substitute the values into the equations to get the final answer.