Link up the force types with a pictures. Explain your choices! Bell Task Forces Link up the force types with a pictures. Explain your choices! Tension force Frictional force Reaction force Magnetic force Weight force Air Resistance force Electrostatic force Upthrust force Thrust force

Forces and their Effects KS3 Physics Forces and their Effects

Forces L.O.: Explain how forces can affect objects. Learning Outcomes L.O.: Explain how forces can affect objects. Must: know that a force is the push, pull or twisting of an object. Should: be able to name some contact and non-contact forces and know the difference between the two. Could: explain using examples of how forces can affect the shape, speed and direction of an object.

What is a force? Connect A force is a push or a pull. A force cannot be seen but you can see how a force affects an object.

What type of force? Connect

When forces are balanced Connect balanced forces 10 N 10 N If you link two newton meters and pull equally hard from both ends, the forces recorded on both will be the same. The forces acting on the central hooks cancel each other out – they are equal in magnitude (size) and opposite in direction. Because the forces are balanced the hooks do not move.

When forces are unbalanced Connect unbalanced forces 11 N 10 N movement What happens if the pull on one end is greater than the pull on the other end? The forces acting on the hooks are no longer balanced. Both hooks will start to move to the left – their speed will change. This is called acceleration. Unbalanced forces lead to a change in speed or direction.

Balanced or unbalanced forces? Connect In which direction will these stationary objects move?

Which forces are contact forces and which are non-contact forces? Activity Forces Which forces are contact forces and which are non-contact forces? Tension force Frictional force Reaction force Magnetic force Weight force Air Resistance force Electrostatic force Upthrust force Thrust force

Forces Share new Information Contact and non-contact forces A contact force is a push or a pull on one object by another object that is touching it. An applied force is a type of contact force in which one object directly pushes or pulls on another object. For example, in tug of war, you apply a pulling force to the rope. A spring force (or elastic force) is the force exerted by a bending or stretching object on any object that is attached to it.

Forces Share new Information What are some contact forces? Friction is the force an object exerts on another object that moves across it. The force of friction is always in the opposite direction to the motion of the object. Friction tries to slow an object’s motion. Air resistance is a type of contact force that air exerts on moving objects. Like friction, air resistance tends to oppose the motion of an object.

Forces From a Distance Share new Information What are some non-contact forces? A force that pushes or pulls on an object without touching it is called a non-contact force. A magnetic force is a non-contact force that exists between certain materials, such as magnetised iron. The force may be attractive (like a pull) or repulsive (like a push).

Forces Share new Information What are some non-contact forces? An electrical force acts between objects that are electrically charged. It is a type of non-contact force. Objects with like charges tend to repel (push) one another. Objects with unlike charges attract (pull) one another. Gravitational force is a non-contact force of attraction that exists between any two objects that have mass. On Earth, we experience gravity as a downward force.

Which forces are contact forces and which are non-contact forces? Activity Forces Which forces are contact forces and which are non-contact forces? Tension force Frictional force Reaction force Magnetic force Weight force Air Resistance force Electrostatic force Upthrust force Thrust force

Demonstrate Understanding Watch the following video clip. Forces Watch the following video clip. Either by yourself or with a partner, discuss what forces can do to objects.

Demonstrate Understanding Forces

speeds up again (speed change). Forces Share new Information Forces : forces are basically just pushes, pulls and twists! We measure forces in Newtons (N). Forces can change:- the speed of an object the direction that an object is moving in the shape of an object. The bat slows down the ball (speed change). The ball gets squashed on impact (changes shape). The bat redirects the ball (changes direction) and the ball speeds up again (speed change).

Forces Demonstrate you can do these! Learning Outcomes Demonstrate you can do these! Must: know that a force is the push, pull or twisting of an object. Should: be able to name some contact and non-contact forces and know the difference between the two. Could: explain using examples of how forces can affect the shape, speed and direction of an object.

Stand Up – Hands Up Review and Reflect Forces You have to Hi-5 at least 3 other people in the classroom and tell them something new you have learned today. They will then tell you something different that they have learned today. and Reflect