FearOfPhysics.com: Homework Help

Physics Problems (video solutions)

Statics

Person walking on a plank. How far can they walk before it tips?

Angle a ladder can be placed without slipping.

What are the support forces for a plank with a person walking on it?

A person sitting on a beam supported by a cable. What are the hinge forces and the tension in the cable?

A crane holding a weight. What are the hinge forces and the tension in the cable?

A merry-go-round with four forces on it. What is the net torque?

A sphere that rolls up an incline. How high will it go?

A rod with two forces on it. What is the net torque?

Two forces are acting on a pulley. What is the net torque on it?

The acceleration of an Atwood Machine with a real pulley. What is its acceleration?

Rotational Motion

Rotation of car tires for a large and small car. How do the omegas compare?

Conservation of Momentum

Two ice skaters pushing away from each other. What are their final speeds?

A bunch of railway cars crashing into one another. What are their final speeds?

A firecracker exploding. What are the speeds of its fragments?

A dart embedding into a falling cork. What are the final speeds?

A bullet embedding into a block. What are the final speeds?

Two billiard balls colliding. What are their final speeds?

Conservation of Energy

A box sliding down a hill onto a friction ramp

A box shot up a ramp by a spring

A box shot across a patch of friction by a spring

A box shot up a ramp by a spring that encounters a friction patch first

A person who jumps on a sled then slides down a ramp into a spring

A person on a ski jump

A heavy block being dropped onto a spring

A block sliding down an incline into a spring

Forces and Newton's Laws

A block hanging from a rope. What's the tension when the block accelerates up/down/and is held at rest?

A ball shot from an air gun. How high will it go?

A piano being lowered by three ropes. What are the tensions?

A block held against a wall. What are the forces on it?

Projectile Motion

A ball thrown at some angle above the ground. How far will it go?

A tennis serve. Will the ball clear the net?

A cannon ball being shot off of a cliff. How far will it go?

A ball being launched toward a cliff. Will it make it onto the cliff?

Free fall motion

A rocket being launched straight up. How high will it go and how long will it be in the air?

One dimensional motion

Two people trying to catch each other

A car driving between two trees. What is its speed and acceleration

Various questions about the motion of an elevator speeding up/cruising/then slowing down

Electric Field

Find the electric field outside of a glass bead.

Find the electric field at the center of three charges on a circle.

Find the electric field outside of an electric dipole

Find the electric field in the space near two charged glass rods

Find the electric field around two charged rings

Find the electric field in between two infinite line charges

Find charges on and field around two charged disks

Coulomb's Law

What is an unknown charge to make the Coulomb force balance on another charge.

Moving Charge in an Electric Field

Motion of an electron shot between two parallel charged plates

A charge is fired between two capacitor plates. What is the potential and speed of the charge?

A proton fired between two parallel plates. Find things about its motion.

Electric Potential

What are the field and potentials between the plates of a parallel plate capacitor

Electric Potential Energy

What is the potential energy due to three charges?

What is the potential energy at the corner of a square where the other 3 corners have charges?

Capacitance

Find capacitance and charge on two aluminum electrodes.

Capacitors in a circuit

Find the charge flowing onto a capacitor when a switch is closed.

Find the potential difference on capacitors in a circuit.

Charge a capacitor in a circuit by closing a switch?

Equivalent Capacitance

Find the equivalent capacitance of 3 capacitors.

Find the equivalent capacitance of two different circuits.

Find the equivalent capacitance and charge on capacitors in series.

Equivalent Resistance

Find R given 2 other resistors and a current flowing.

Question involving the internal resistance of a battery.

Find R for resistors in parallel given a voltage and current.

Find R for resistors in series with a current flowing.

Resistor Capacitor (RC) Circuits

Analyze a DC circuit involving a capacitor resistor and switch.

Discharging a capacitor through a resistor.

DC Circuits

Analyze a switch thrown between two series resistor legs in a DC circuit.

Biot-Savart Law

Find the magnetic field (B-field) due to two current carrying wires.

Use Biot-Savart to find the magnetic field (B-field) due to a moving charge.

Use Biot-Savart to find the B field due to two semicircular wires.

Use Biot-Savart to find the B field due to an arc of wire

Use Biot-Savart to find the B field due to a proton at a few points in space

Lenz's and Faraday's Laws

Use Lenzâ€™s law to ID magnetic field strength inside of a loop.

Find the potential difference of a wire falling in a B-field.

A segment of wire pulled on a U-shaped segment in a B-field.

Find the induced current in a coil of wire.

Find the current in a solenoid.

Find current induced in a hand cranked generator.

Magnetic Flux

Find the magnetic flux through a rectangular loop of wire.

Find the magnetic flux through a triangular wire.

Mechanics Problems (text-based solutions)

One Dimensional Motion(20)

Two Dimensional Motion(10)

Forces and Newton's Law(24)

Conservation of Energy(16)

Conservation of Momentum(10)

Rolling and Angular Momentum(10)

Oscillations(5)

Gravity(5)

Electricity and Magnetism (E+M) (text solutions)

Coulomb's Law(11)

Electric Fields(14)

Electric Potential(10)

Capacitance(13)

DC Circuits(20)

Charges in Magnetic Fields(7)

Currents and Magnetic Fields(7)

Faraday's Law and Lenz's Laws(9)

AC Circuits(5)

Miscellaenous(2)

RC Circuits(2)

Optics: Snell's Law(4)

Optics: Mirrors and Lenses(6)