Force and motion

Disadvantages of friction force

Walk/Write

Hold things

Drive/Stop a car

Advantages of friction force

Slow down movement

Noise

Heat

Different types of motion of the object gives rise to different types of friction. Generally, there are 4 types of friction. They are static friction, sliding friction, rolling friction, and fluid friction.

What is a moment? = The Moment of a force is a measure of its tendency to cause a body to rotate about a specific point or axis.

Moment = Force x Distance or M = (F)(d)

Class of Levers

There are three types or classes of levers, according to where the load and effort are located with respect to the fulcrum. Class 1 has the fulcrum placed between the effort and load, Class 2 has the load in-between the effort and the fulcrum, and Class 3 has the effort between the load and the fulcrum.

First Law - Inertia

Object tend to stay in the same position.

Second Law - F=ma

Force is proportional to mass times acceleration.

Third Law - Action Reaction

Every force has an equal and opposite reaction force.

When an object is placed in a fluid, the fluid exerts an upward force we call the buoyant force.Because the pressure increases as the depth increases, the pressure on the bottom of an object is always larger than the force on the top.

Who discovered buoyancy? = Achimedes

Density tells us if the object floats or sinks.

Buoyancy more than weight = float

Buoyancy equal to weight = hover

Buoyancy less than weight = sinks

Motion = An objecr is in motion if it changes its position with time

Rest = An objecr is at rest if it does not change its position with time

Rest/Motion

Linear

Rectilinear

Curvilinear

Free fall

Projectile

Circular

Centrifugal force

Rotary

Oscilatory