SME
College · Science
University Physics I: Mechanics
10 topics
Physics
Before this course
Topics
Kinematics
Main lesson
Velocity and acceleration from x(t)
Use this for “x = 2t³ − 9t² + 12t + 4 (m, s). Find the velocity and acceleration at t = 3 s.”
A projectile’s position and velocity at a time
Use this for “A ball is thrown from 2 m up at 20 m/s, 60° above level. Where is it 2.5 s later, and how fast and which way is it moving?”
Newton's laws
Main lesson
An Atwood machine: two hanging blocks
Use this for “Blocks of 3 kg and 5 kg hang from the two ends of a string over a pulley. Find their acceleration and the string’s tension.”
Falling against linear drag: terminal speed
Use this for “A 2 kg ball is dropped from rest, and the air pushes back with 4 kg/s times its speed. Find its terminal speed and how fast it falls after 1 s.”
A banked curve with no friction: the design speed
Use this for “A curve of radius 80 m is banked at 12°. At what speed can a 1500 kg car take it with no friction, and how hard does the road push on it?”
Work and energy
Main lesson
Work by a force F = cxⁿ
Use this for “A force F = 0.5x³ N pushes a cart along a track from x = 2 m to x = 4 m. How much work does it do?”
Force and equilibrium from U(x) = ax³ − bx²
Use this for “A particle has potential energy U(x) = 2x³ − 6x² (U in J, x in m). Find the force on it at x = 0.5 m, and where it can rest in stable equilibrium.”
Energy down a rough slope: heat and the end speed
Use this for “A 40 kg sled starts down a 50 m slope at 20° moving at 3 m/s, with μₖ = 0.08. How much heat does friction make, and how fast is the sled at the bottom?”
Momentum
Main lesson
An elastic collision in 1D, both moving
Use this for “A 0.5 kg puck sliding east at 3 m/s catches a 1.5 kg puck sliding east at 1 m/s, and they bounce apart elastically. What are their velocities after?”
Center of mass of masses on a line
Use this for “A light 1.2 m rod holds 0.4 kg at 0.1 m, 0.6 kg at 0.5 m and 1 kg at 1.1 m. Where is its center of mass?”
Impulse from a triangular force pulse
Use this for “A kick pushes a 0.43 kg ball at rest with a force that rises evenly to 2,400 N and falls back to 0 over 8 ms. What is the impulse, and how fast does the ball leave?”
The rocket equation
Use this for “A 12,000 kg rocket burns fuel until it weighs 4,000 kg, its exhaust leaving at 3,000 m/s. How much speed does it gain?”
Rotation and torque
Main lesson
The parallel-axis theorem for a rod
Use this for “A 2 kg rod 1.5 m long turns about an axis 0.5 m from its center. Find its moment of inertia about that axis.”
A block falling from a pulley with mass
Use this for “A 3 kg bucket hangs from a rope wound round a 5 kg solid disk pulley of radius 0.2 m. Find the bucket’s acceleration, the rope’s tension and the pulley’s angular acceleration.”
A spinning skater pulls in her arms
Use this for “A skater spinning at 3 rad/s with her arms out (I = 5 kg·m²) pulls them in to I = 2 kg·m². Find her new spin and the work her arms do.”
A ladder against a smooth wall: will it slip?
Use this for “A 300 N ladder leans on a smooth wall at 65° to the floor. How hard does the wall push, and how rough must the floor be to hold it?”
Oscillations
Main lesson
A damped oscillator: its frequency, Q and fading amplitude
Use this for “A 2 kg block on a 200 N/m spring has damping b = 1 kg/s and starts with a 0.1 m amplitude. Find ω′, Q and the amplitude after 4 s.”
A physical pendulum: a rod swinging from its end
Use this for “A 0.3 kg rod 1.2 m long swings from a pin at one end. Find its period and the length of a simple pendulum that keeps time with it.”
Gravitation
Fluid mechanics
Temperature, heat and kinetic theory
Main lesson
The final temperature of a mixture
Use this for “A 0.2 kg aluminium block at 90 °C goes into 0.5 kg of water at 20 °C. Find the final temperature.”
Heat flow through a wall
Use this for “How much heat flows through a concrete wall 10 m² in area and 20 cm thick when inside and outside differ by 20 °C?”
First and second laws of thermodynamics
Course test
See what you know: 10 questions on this course
New questions each time. Pass to mark it complete.