Machines and Conservation

Momentum

A vector quantity that has the same direction as the velocity of the object.

Impulse

A vector quantity that has the same direction as the force.

m*v

Momentum’s formula.

F*t

Impulse’s formula.

equal

Momentum is ___ to Impulse.

Elastic Collision

When both momentum and kinetic energy are conserved.

m1v1 + m2v2 = m1v1’ + m2v2’

Conservation of momentum and energy.

½m1v1² + ½m2v2² = ½m1v1’² + ½m2v2’²

Conservation of kinetic energy.

Inelastic collision

When either momentum/kinetic energy is not conserved.

m1v1 + m2v2 = m(1+2) * v(final)

Conservation of momentum not energy.

(m1v1)*cos0

Momentum of one afterwards

Potential energy

Stored energy, the gravitational one is due to the position of an object above the Earth’s surface.

Kinetic energy

The energy of motion.

m*g*h

Gravitational potential energy’s formula.

F*d

Work’s formula.

½m*v²

Kinetic energy’s formula.

Joules

All energy and work is measured in ___.

PE + KE

Mechanical energy’s formula.

mgh = ½*m*v²

Top PE = Bottom KE

Simple machine

An object or mechanical device that receives an input amount of work and transfers the energy to an output amount of work.

Inclined plane

The simple machine consisting of a sloping surface, used for raising heavy bodies

Screw

An inclined plane wrapped around a cylinder.

Wedge

Essentially two inclided planes back to back.

Lever

The simple machine that is consisted of an inflexible of material placed over a pivot point called a fulcrum.

Pulley

A wheel on an axle that is designed to rotate with movement of a cable along a groove at its circumference.

Wheel and axle

The simple machine that is composed of two connected cylinders of different diameters.

W/t = F*v

Power’s formula.

E = (out/in)*100% = (AMA/IMA)*100%

Efficiency’s formula.

IMA = d(in)/d(out)

The ideal mechanical advantage’s formula.

AMA = F(out)/F(in)

The actual mechanical advantage’s formula.

W(in)/t

Effort power.

W(out)/t

Resistance power.

F(in)*d(in)

Effort work.

F(out)*d(out)

Resistance work.

F(out)/IMA

Effort force’s formula

Power

The rate at which work is done or the rate at which energy is transformed.

Work

The transfer of energy by a force acting on an object as it is displaced.