Have you ever wondered about the invisible forces that affect you every day? One way to understand these forces is by using something called a free body diagram. This is a simple drawing that shows all the forces acting on an object using arrows. The length of each arrow represents how strong the force is, and the direction of the arrow shows which way the force is pushing or pulling.
At any moment, different forces are acting on you. The most obvious one is gravity, which pulls you down toward the Earth. But there’s another important force that you might not think about: the force from the ground pushing you up.
It might seem strange to think of the ground as pushing on you, but it really does! Imagine standing on a spring. When you step on it, the spring gets squished, and it pushes back up against you. This upward push from the spring helps balance out the downward pull of gravity, keeping you still.
The ground works in a similar way. When you stand on it, you press down slightly, and the ground pushes back up. This upward force is called the normal force. It’s just as strong as the gravitational force pulling you down, so you don’t move.
To sum it up, there are two main forces acting on you:
The word “normal” here means that the force is at a right angle to the surface you’re standing on. In free body diagrams, these forces are often shown acting through the center of mass of the object, even though they actually come from where your feet touch the ground.
Understanding these forces and how they work together is a key part of learning about physics and how things move. By using free body diagrams, you can get a clearer picture of the forces at play and how they affect motion.
Draw a free body diagram of yourself standing still. Use arrows to represent the gravitational force pulling you down and the normal force pushing you up. Make sure the arrows are of equal length to show that these forces are balanced. Label each force clearly.
Find a spring scale and a small object, like a book. Measure the gravitational force acting on the book by attaching it to the spring scale. Record the force in newtons. Then, draw a free body diagram of the book, showing the gravitational force and the normal force when the book is resting on a table.
Use an online physics simulation to explore how different forces affect an object. Adjust the strength of the gravitational force and the normal force, and observe how the object moves. Take screenshots of different scenarios and create free body diagrams for each one.
Work in pairs to balance a ruler on a pencil. Place different objects on either side of the ruler and adjust their positions to keep the ruler balanced. Draw a free body diagram for the balanced ruler, showing the forces acting on it, including the gravitational forces of the objects and the normal force from the pencil.
Go outside and observe different objects, like a parked car or a tree. Think about the forces acting on these objects. Choose one object and draw a free body diagram, showing the gravitational force and the normal force. Discuss with your classmates how these forces keep the object stationary.
Forces – Forces are pushes or pulls that can cause an object to move, stop, or change direction. – When you kick a soccer ball, you apply a force that makes it move across the field.
Gravity – Gravity is the force that pulls objects toward the center of the Earth or any other celestial body. – The apple fell from the tree because gravity pulled it toward the ground.
Normal – In physics, a normal force is the support force exerted upon an object in contact with another stable object. – When a book rests on a table, the table exerts an upward normal force on the book.
Diagram – A diagram is a simplified drawing that represents the components of a system or process. – The teacher drew a diagram on the board to show how the forces act on a moving car.
Object – An object is a material thing that can be seen and touched, and in physics, it is often the subject of study for its motion and forces. – The object in the experiment was a small wooden block that we pushed across the table.
Ground – The ground is the solid surface of the Earth, which can exert forces such as friction and normal force on objects. – When you walk, the ground pushes back against your feet, allowing you to move forward.
Push – A push is a force that moves an object away from the source of the force. – She gave the swing a push to make it move higher.
Pull – A pull is a force that draws an object closer to the source of the force. – The magnet can pull small metal objects toward it.
Motion – Motion is the change in position of an object over time. – The motion of the planets around the sun is due to gravitational forces.
Balance – Balance is the state in which all forces acting on an object are equal and opposite, resulting in no change in motion. – The tightrope walker maintained her balance by holding a long pole.
