## Drawing free-body diagrams with examples

The rotation of the wheel causes point A on the car tyre to move at 8.9 m/s, and the rest of the car is moving at 8.9 m/s. This means that relative to the ground, point A is traveling at 8.9 + 8.9 = 17.8 m/s.
More bizarrely, due to the rotation of the wheel, point B on the car tyre is going backwards at 8.9 m/s while the rest of the car is moving forward at 8.9 m/s. As a consequence, Point B is temporarily stationary in relation to the field.
Since the contact points on each tyre are stationary with respect to the road surface while they are in position B, the tyres will ‘grip’ the road surface. If this were not the case, the vehicle would be difficult to handle due to the fact that it would be in a skid.
If the car in the diagram is four-wheel drive, the total force needed to propel it forward is 4 x 330 N = 1320 N. Since it is traveling at a constant speed, the resulting force is zero (or total force). As a consequence, the gross resistive force acting on the car is calculated to be 1320 N.

## Free-body diagrams

It is sometimes important to draw pictures in order to be able to examine forces and their consequences. The powers and where they work are the most important aspects of these images. Anything that isn’t necessary is removed in such images. The diagrams are known as free-body diagrams.
To make sense of them, we must first create a common nomenclature, or a system for labeling all. Let’s begin with the powers. The way forces work on an entity distinguishes them. There are two types of forces: touch and non-contact.
Non-contact forces do not enable the subjects to make physical contact in order for them to communicate. The most powerful non-contact force is gravitational force, which is responsible for all objects’ weight and is denoted by the letter W. The magnetic force and the electric force are two other non-contact forces that are discussed in this course.
For obvious purposes, contact forces are divided into pushes and pulls. Tension is the name given to the pull force in order to differentiate it from the push force, which is named P. Only when cords, ropes, chains, or your hair are involved do tension forces work. The angle at which a force is applied defines the force. Standard forces are those that are applied perpendicular (or normal) to the surface. Friction forces are generated when they are applied parallel to the surface. To differentiate friction from the force mark “F,” friction is identified with a lower case f.

### Free body diagram of car on a slope

The study of dynamics is what happens when you touch the brakes in a car and come to a complete halt, or what happens when a parachutist leaps out of a plane and falls faster and faster.

### Free body diagrams and types of forces

The study of the causes of various movements, both uniform and non-uniform, is known as dynamics.
Something must act on an object in order for it to adjust its speed: the object must be pushed or pulled in a particular direction. The Earth’s gravity is pushing our parachutist closer to the surface, allowing her to accelerate. As she deploys her parachute, it pulls her upward and causes her to slow down. And when she collides with the Earth (hopefully gently! ), the Earth pulls on her, causing her forward motion to slow down and finally come to a halt.
Forces are the pushing and pulling interactions between objects. Any two objects will exert a force on each other if they are communicating with each other. Remember that things don’t have to be touching to interact; for example, the Earth can still exert gravity on an airplane in mid-flight.

### Fbd calculations car

The careful drawing of a free-body diagram is the first step in explaining and examining most phenomena in physics. Throughout this chapter, free-body diagrams have been used as examples. Keep in mind that a free-body diagram can only show the external forces acting on the subject body. If the body is in equilibrium (balanced forces; that is, we have drawn an accurate free-body diagram), we can apply Newton’s first law.
Notice that we do not explicitly include acceleration in the free-body diagram if it exists; however, indicating acceleration beyond the free-body diagram can be useful. It can be colored with a different color to differentiate it from the free-body diagram. Part (b) depicts a free-body diagram for this case, as defined in the problem-solving strategy’s steps 1 and 2. Following phase 3, we show all forces in terms of their x– and y–components in section (c).
Graph 5.32 (a) Isolated object A’s free-body diagram. (b) Isolated object B’s free-body diagram. When we compare the two sketches, we can see that friction works in the opposite direction in both. Friction must behave to the left because object A is subjected to a force that pulls it to the right. Since part of the weight of object B pushes it to the left, down the incline, the friction force must oppose it and act up the ramp. Friction still works in the opposite direction of motion.