Forces & Megastructures In creating the greatest megastructures on earth, forces are the one of the most important scientific components which impact on construction and development...

Forces in Action Why doesn’t gravity make you fall through the floor? Why do some athletes shave their necks, head and arms? How fast do skydivers fall through the air? How does a seatbelt protect you in a car accident?

What is a Force? A force is something that makes something or someone move. - A force is a PUSH, PULL or a TWIST. - Force is measured in units called Newtons (N).

Push Click on the 2 pictures that show something being pushed. twist pull pull

Pull Click on the 2 pictures that show something being pulled. twist push

Twist Click on the 2 pictures that show something being twisted. pull push push

Balanced Forces If two equal forces are applied to an object in opposite directions, the object does not move / or moves as a constant speed. This is called balanced forces. ARM WRESTLERS...

Unbalanced forces If two unequal forces are applied to an object in opposite directions, the object does move. This is called unbalanced forces.

Unbalanced Forces If the forces acting on an object are not balanced then the object with either: Speed up Slow down Change direction Change its shape

Example… When a tennis ball hits a racket, it is obvious that a force is acting on the ball... There is also a force acting on the racket as well...

Forces can start motion Forces can stop motion Speed up motion Change the direction of motion Have no effect at all Changes the shape of objects Slow down motion

Types of Force CONTACT FORCE Friction: A force that acts against the movement of an object. It occurs between any surfaces that are touching and trying to move past each other. Buoyancy: An upward acting force exerted by liquid, that opposes an object’s weight. NON-CONTACT FORCE Gravity: The force of attraction that exists between any two bodies in the universe that have mass. Gravity pulls objects to the centre of the Earth. Magnetics: An invisible force that either attracts or repels magnetic objects eg. Metals. Electrostatics: An invisible force that is generated by electrostatic energy.

Examples in everyday life Complete the following… Effect Examples in everyday life Starting a motion Stopping a motion Speeding up a motion Slowing down a motion Changing the direction of motion Changing the shape of an object Having to visible effects

Force can be divided into The following… Gravity Magnetics Air resistance Friction Newton’s Laws of Motion