Work, Energy, and Power Flashcards

Study Notes

Energy and Work

Energy is the capacity to perform work.
Work occurs when a force is applied over a distance, requiring direction alignment between force and distance.
Work is quantified by the formula: W = Fd cos(theta), measured in joules (Newton * meter).

Angle Considerations in Work

When θ = 0: cos(0) = 1; work is maximized as the object moves positively.
At θ = 90 degrees: cos(90) = 0; no work is performed.
If θ > 90 degrees: work is negative, indicating opposing direction.
If θ < 90 degrees, work is positive; total work can be calculated as w_net, the sum of all forces.

Characteristics of Work

Work is only performed when force components are parallel to displacement.
It is a scalar quantity, which can be positive or negative based on force direction relative to displacement.
Positive net work accelerates the object, while negative net work results in deceleration.

Hooke's Law and Springs

Hooke's Law focuses on spring mechanics, governed by force, stiffness, and spring constant (k, N/m).
The equation for Hooke's Law is F = kx, where k indicates stiffness, and x represents elongation or compression.

Energy Types

Kinetic Energy (KE) depends on mass and velocity, defined as KE = 1/2 mv² (measured in joules).
Gravitational Potential Energy (PEg) relies on mass, height, and gravity, expressed as PEg = mgh.
Elastic Potential Energy is given by PE elastic = 1/2 kx², based on spring stiffness and compression/stretch distance.

Energy Conservation

The principle of conservation of energy states that total mechanical energy (KE + PE) remains constant in a closed system without friction.
The relationship between net work and kinetic energy is expressed as W - KE Theorem: net work equals change in kinetic energy.

Power

Power quantifies the rate at which work is accomplished, defined as P = W/t (watts = joules/second).
An alternate formula for power is P = Fv, combining force and velocity for calculations.

Description

These flashcards cover fundamental concepts of work, energy, and power. Learn key definitions and important equations that describe the relationship between these physical quantities. Ideal for students looking to reinforce their understanding of physics.