Question

lester in the pe department is pushing a 88.4-kg load of towels at constant speed a distance of 23.7 meters using a horizontal force of 179 newtons. determine the work done by friction.

Answer 1

The work done by friction while pushing an 88.4-kg load of towels for a distance of 23.7 meters with a horizontal force of 179 newtons is -4233.3 joules, indicating that friction is doing work in the direction opposite to the displacement.

Step-by-step explanation:

The student who asked the question wants to determine the work done by friction while pushing a load horizontally. Work done by friction can be calculated as:

Wfriction = Ffriction × d × cos(180°), where:

• Ffriction is the force of friction,
• d is the distance the load is pushed,
• cos(180°) is the cosine of the angle between the force of friction and displacement, which is -1 since they are in opposite directions.

Because friction is opposing the motion and the displacement is in the opposite direction of the frictional force, the work done by friction will be negative.

Here's the calculation for the provided scenario:

• Ffriction = 179 N (given as the horizontal force needed to push the load at constant speed, implying an equal and opposite frictional force),
• d = 23.7 m,
• cos(180°) = -1 (opposite directions).

Thus, the work done by friction is:

Wfriction = 179 N × 23.7 m × (-1) = -4233.3 J.

The negative sign indicates that the work done by friction is in the direction opposite to the displacement.

Answer 2

To determine the work done by friction, we need to calculate the frictional force using the coefficient of kinetic friction and the normal force. The work done by friction can then be calculated using the formula for work. However, the coefficient of kinetic friction is missing from the given information, so we cannot determine the exact value.

Step-by-step explanation:

First, we need to calculate the frictional force acting on the load. The horizontal force applied by Lester is equal in magnitude but in the opposite direction to the frictional force. Using the formula for frictional force, we can calculate:

Ffriction = μK * Fnormal

where μK is the coefficient of kinetic friction and Fnormal is the normal force.

However, the normal force is equal in magnitude but in the opposite direction to the weight of the load, which is given by:

Fnormal = m * g

where m is the mass of the load and g is the acceleration due to gravity.

Therefore, the work done by the frictional force can be calculated as:

Workfriction = Ffriction * d * cos(180°)

where d is the distance over which the load is pushed, and cos(180°) is equal to -1.

Plugging in the given values, we have:

mass (m) = 88.4 kg

horizontal force (F) = 179 N

distance (d) = 23.7 m

coefficient of kinetic friction (μK) = ?

With the given information, we are missing the coefficient of kinetic friction. Please provide the value of μK in order to calculate the work done by friction.