Question

Learning Goal: To gain practice drawing free-body diagrams

Whenever you face a problem involving forces, always start with a free-body diagram.

To draw a free-body diagram use the following steps:

1. Isolate the object of interest. It is customary to represent the object of interest as a point in your diagram.

2. Identify all the forces acting on the object and their directions. Do not include forces acting on other objects in the problem. Also, do not include quantities, such as velocities and accelerations, that do not force.

3. Draw the vectors for each force acting on your object of interest. When possible, the length of the force vectors you draw should represent the relative magnitudes of the forces acting on the object.

In most problems, after you have drawn the free-body diagrams, you will explicitly label your coordinate axes and directions. Always make the object of interest the origin of your coordinate system. Then you will need to divide the forces into x and y components, sum the x and y forces, and apply Newton's first or second law.

In this problem, you will only draw the free-body diagram.

Part B

Identify the forces acting on the object of interest. From the list below, select the forces that act on the piano.

Check all that apply.

• accelerationof the piano

• gravitational force acting on the piano(piano's weight)

• speed of the piano

• gravitational force acting on Chadwick(Chadwick's weight)

• force of the floor on the piano (normal force)

• force of the piano on the floor

• force of Chadwick on the piano

• force of the piano pushing on Chadwick

Answer 1

Concepts and reason

The concept behind the question is free body diagrams. The main purpose of a free body diagram is to reduce the complexity of situation for easy analysis.

Initially, draw a free-body diagram in the solving of mechanic’s problems.

Another concept to solve this question is force. Forces are from the interaction of two

objects in contact with each other.

Fundamentals

Free body diagram is a tool for solving problems with multiple forces acting on a single body.

A force diagram is simply a diagram showing all the forces acting on an object, the force’s direction and its magnitude.

Important points for drawing a force diagram are,

1.Isolate the object of interest and consider it is a point in the diagram.

2.Identify all the forces acting directly on the object.

3.Draw a vector to represent each force. Draw it in the direction the force is being exerted, and label it by the type of force, the object exerting the force, and the object receiving the force.

A force is a push or pull on an object. This push or pull comes from the objects interacting with one another.

Contact forces are Friction, air resistance, applied force, tension force, and spring force.

No-contact forces are Gravity, magnetic force, electric and nuclear force.

Draw the free body diagram of piano as follows:

Consider the piano is at rest initially. The gravity is pulling the piano towards downwards and there is a force of the floor on the piano upwards. Consider the applied force on the piano towards right.

(b)

Identify the forces acting on the object of interest as follows:

Consider the piano is at rest initially. The gravity is pulling the piano towards downwards and there is a force of the floor on the piano upwards. Consider the applied force on the piano towards right

Therefore, the list of forces acting on the piano is shown below:

2. Gravitational force acting on the piano (piano’s weight)

5. Force of the floor on the piano (normal force)

7. Force of Chadwick on the piano.

Ans: Part a

The free body diagram of the piano is,

Part b

The forces that act on the piano are,

2. Gravitational force acting on the piano (piano’s weight)

5. Force of the floor on the piano (normal force)

7. Force of Chadwick on the piano.