MYP Physics Forces and Effects of Forces Notes

What Is a Force and What Does It Explain?

1. Forces are how objects interact.
2. In everyday language, a force is a push or pull, but in physics, it also includes "invisible" interactions such as gravity, magnetism, and electrostatic attraction/repulsion.
3. The key idea is that a force can change an object's velocity (speed or direction) or change its shape.

How Forces Change Motion

1. A force can make an object start moving from rest.
2. A force can make a moving object speed up.
3. A force can make a moving object slow down or stop.
4. A force can make an object change direction, even if its speed stays the same.

How Forces Change Shape (Deformation)

1. Forces can stretch objects, such as pulling on an elastic band.
2. Forces can compress objects, such as squeezing a sponge.
3. Forces can bend or squash objects, causing permanent or temporary deformation.

Non-Contact Forces

1. Non-contact forces act through fields and do not require physical contact.
2. Objects experience these forces when they enter a region of influence around another object.

1. Gravitational Force (Weight)

1. Earth pulls objects toward its centre.
2. This pulling effect is responsible for objects falling when dropped.
3. The gravitational force acting on an object is called its weight.
4. Weight depends on both the object’s mass and the strength of the gravitational field.

2. Electrostatic Force

1. Electrostatic forces act between electrically charged objects.
2. These forces can attract or repel depending on the type of charge.

3. Magnetic Force

1. Magnetic forces act between magnets or magnetic materials.
2. Opposite poles attract, while like poles repel.
3. Magnetic forces can act through air and other materials.

Contact Forces

1. Contact forces only act when objects are touching.
2. These forces often occur in pairs where objects push or pull on each other.

1. Normal Force