First let's draw a free body diagram of the block with all the forces acting on it.

The block has a weight force which is . The normal force is equal and opposite (otherwise the block would be accelerating into the ground or into the air. The applied force is at an angle, and in order to find the work done we need to find the applied force that is pulling the block across the floor. This is:

The work done is just the product of the applied force and the distance the block slides,

Work is an energy, and the units of  are equal to Joules.

In order to find the work done on the object, we need to take the dot product of the force and the path taken. This is a direct calculation.

Because all of the force was in the Y direction, all of the work will come from the change in the Y coordinate.

We will use the definition of work

First we need to find the distance traveled.

Then we can plug that into our work equation.

The definition of work is

Where

 is Force

 is displacement

and  is the angle between the displacement and the force.

The angle will be because the dolly is traveling horizontally and the rope which is applying the force is above the horizontal.

We plug in our values

Use the definition of work:

Plug in known values and solve.

All of the is kinetic energy

Convert  to and plug in values:

Solve for

Use work:

All energy will be kinetic.

Convert  to :

Plug in values. Force will be negative as it is directed against the direction of travel:

Solve for :

Work is defined as:

Where  is work,  is force experienced by the object/person, and  is the distance the object/person moves as a result of the force. Recall that force is calculated as follows.

Where  is mass and  is acceleration; therefore, work depends on the mass and acceleration (force), and distance.

To solve this question, we need to recall the definition of work.

 is work,  is force, and  is distance. Force is defined as:

To calculate work, we need to know about the distance travelled, mass, and acceleration. The question gives us the distance and mass but it doesn’t give us the acceleration of the object; therefore, we cannot calculate the work done by the person. Note that if the question gave us the force applied by the person, then we will be able to calculate the work without mass and acceleration.

Recall that work can be defined as the change in energy of a system. For most systems, we deal with two types of energy: potential and kinetic energy; therefore, work is defined as follows.

Where  is work,  is change in kinetic energy, and  is change in potential energy. Work can be negative or positive based on the type of work being performed. If work is done by an on object (such as object A) then it will have a positive value for work. However, if work is being done on the object (such as object B) then the object will have a negative value for work. We already defined work as being the sum of change in potential energy and change in kinetic energy; therefore, this sum will be positive for object A (positive work) and negative for object B (negative work). Note that both object A and object B will have the same, absolute value for work.