Science Physics

Force

A push or a pull or twist

Buoyancy

The ability of a fluid to exert an upward force on an object placed in it

Achimedes' Principle

when an object is placed in a fluid, the fluid pushes up on it with a force equal to the weight of the fluid the object displaces. If this upward force is greater than the object's weight, it floats; if it's less, the object sinks.

static friction

The object does not move, when a applied force is not big enough to over come the frictional force

kinetic energy

the friction between two or more moving surfaces. This could be sliding or rolling

Friction

A force that opposes motion between two surfaces that are in contact

How to increase friction

Make surface rougher or bumpier e.g. sand on icy roads to stop cars from skidding

Newton's Frist Law of Motion

"An object at rest, or in motion, will stay at rest, or in motion, unless acted upon by an outside, unbalanced force."

Newton's Second Law

F = m x a

Force = mass x acceleration

Newton's Third Law

"For every action there is an equal and opposite reaction"

Velocity

the speed of an object with direction

Acceleration

a change in velocity (speeding up or slowing down)

Inertia

The tendency of an object to resist a change in motion

Mechanical Advantage

Contact Forces

are those types of forces that result when the two interacting objects are perceived to be physically contacting each other.

Non contact forces

the types of forces that result even when the two interacting objects are not in physical contact with each other yet are able to exert a push or pull despite their physical separation. 

Constant Force

is speed maintained over time. To achieve a constant speed an object has to cover the for equal intervals over time

Energy

Energy is the ability to do work

Effort

is an applied force to bring desired change to the position

Wedge

variations of an inclined plane

and is a simple machine that changes either the size of a direction of a force

A wedge uses

cut. Knife

split/axe

lever

a simple machine that consists of a rigid bar or plank that pivots around a fixed point called a fulcrum. It is used to move or lift loads with less effort. Levers work on the principle of mechanical advantage, allowing a smaller force to move a larger load by increasing the distance over which the force is applied.

1st class lever

The fulcrum is positioned between the effort (force applied) and the load. An example is a seesaw.

2nd class lever

The load is between the fulcrum and the effort. An example is a wheelbarrow.

3rd class lever

The effort is applied between the fulcrum and the load. An example is a pair of tweezers.

Gravity

is the invisible force that attracts objects toward each other, especially pulling smaller objects toward larger ones like Earth. It keeps planets in orbit, gives weight to objects, and influences the structure of the universe.

The formula for work

W=FxD

Force times distance