Physics Lessons and Labs Study Guide

Unit Conversion

Use conversion factors so the original units cancel and the desired units remain.

What is percent error?

Percent Error = (|Experimental − Actual| / Actual) × 100%

What is percent difference?

Percent Difference = (|Value 1 − Value 2| / ((Value 1 + Value 2)/2)) × 100%

What is precision?

How close repeated measurements are to each other.

What is accuracy?

How close a measurement is to the true value.

What is distance?

The total path traveled by an object (scalar).

What is displacement?

The change in position from start to finish (vector).

What is speed?

Distance traveled per unit time. Equation: v = d/t

What is velocity?

Displacement per unit time with direction. Equation: v = Δx/t

What does the slope of a position-time graph represent?

Velocity.

What does the slope of a velocity-time graph represent?

Acceleration.

What does the area under a velocity-time graph represent?

Displacement.

Equation for acceleration

a = (vf − vi)/t

Equation for position with constant velocity

x = x0 + vt

Equation for final velocity

vf = vi + at

Equation for displacement with acceleration

x = x0 + vit + (1/2)at²

Equation for final velocity squared

vf² = vi² + 2aΔx

How do you describe motion from graphs?

Use the slope and shape of the graph to determine velocity and acceleration.

How do you find the horizontal component of a vector?

Vx = V cosθ

How do you find the vertical component of a vector?

Vy = V sinθ

How do you find the magnitude of a vector?

R = √(x² + y²)

What is projectile motion?

Motion where horizontal and vertical motions are independent.

What is the horizontal acceleration of a projectile?

0 m/s² (ignoring air resistance).

What is the vertical acceleration of a projectile?

-9.8 m/s².

What is a free-body diagram?

A diagram showing all forces acting on an object.

What is net force?

The sum of all forces acting on an object. Equation: Fnet = ΣF

What is Newton's First Law?

An object remains at rest or moves at constant velocity unless acted upon by a net force.

What does equilibrium mean?

Net force equals zero.

What is Newton's Second Law?

Force equals mass times acceleration. Equation: F = ma

What is Newton's Third Law?

Every action force has an equal and opposite reaction force.

What is static friction?

Friction that prevents an object from moving. Equation: Fs ≤ μsN

What is kinetic friction?

Friction acting on a moving object. Equation: Fk = μkN

What is the normal force?

The support force exerted by a surface.

What is centripetal acceleration?

Acceleration directed toward the center of circular motion. Equation: ac = v²/r

What is centripetal force?

The force that keeps an object moving in a circle. Equation: Fc = mv²/r

What is Newton's Law of Gravitation?

Every object attracts every other object with a gravitational force. Equation: Fg = (Gm1m2)/r²

What is Kepler's First Law?

Planets move in elliptical orbits with the Sun at one focus.

What is Kepler's Second Law?

A line from the Sun to a planet sweeps out equal areas in equal times.

What is Kepler's Third Law?

The farther a planet is from the Sun, the longer its orbital period.

What is kinetic energy?

Energy due to motion. Equation: KE = (1/2)mv²

What is gravitational potential energy?

Energy due to height. Equation: PE = mgh

What is spring potential energy?

Energy stored in a compressed or stretched spring. Equation: PE = (1/2)kx²

What is the Law of Conservation of Energy?

Energy cannot be created or destroyed, only transformed.

What is work?

Energy transferred by a force acting over a distance. Equation: W = Fd cosθ

What is power?

The rate at which work is done or energy is transferred. Equation: P = W/t

What is the difference between a scientific law and a scientific theory?

A law describes what happens. A theory explains why it happens.

Why is Excel used in physics labs?

To organize data, perform calculations, and create graphs.

What does the slope of a displacement-time graph represent?

Velocity.

What stays constant during projectile motion?

Horizontal velocity.

What changes during projectile motion?

Vertical velocity due to gravity.

How do you find horizontal and vertical force components?

Fx = F cosθ and Fy = F sinθ.

How can Newton's First Law be used to find an unknown mass?

If the system is in equilibrium, the net force equals zero.

What is the difference between static and kinetic friction?

Static friction prevents motion. Kinetic friction acts during motion.

How do you calculate the coefficient of kinetic friction?

μk = Fk/N

What is rotational speed?

The number of rotations per unit time.

How does rotational speed affect centripetal force?

As rotational speed increases, centripetal force increases.

What happens to potential energy as a skater moves down a ramp?

It is converted into kinetic energy.

How does ramp height affect the skater?

A higher starting position gives more potential energy and greater speed.

Does total energy change in an ideal system?

No. Total energy remains constant due to the conservation of energy.