امثلة واقعية لمواضيع الديناميك (2)

Work

Work = Force x Distance If the wall doesn't move, the prisoner does no work.

Energy

Work is done on the bow. The work done is stored in the bow and string as elastic potential energy. After release, the arrow is said to have kinetic energy, 1/2 mv2. Energy is measured in the same units (joules) as work.

Work and Potential Energy

The work done on the ball gives the ball gravitational potential energy. Gravitational potential energy = mgh

Gravitational Potential Energy

Both blocks acquire the same gravitational potential energy, mgh. The same work is done on each block. What matters is the final elevation, not the path followed.

Energy Transformation

The work done in lifting the mass gave the mass gravitational potential energy. Potential energy then becomes kinetic energy. Kinetic energy then does work to push stake into ground.

Energy Tranformation

E = mgh3 E = mgh2 + 1/2 mv22 E = 1/2 mv12 E = mgh3

Energy Conservation

Total energy is the sum of both types of energy.

Energy Transformation




Power

Power = Work/ Time 1 joule / second = 1 watt

The Lever

Work Out = Work In Small force applied over large distance is the same as large force applied over a small distance.

Lever Example






The Pulley