A cyclist travels 120 m north in 20 s, stops and rests for 10 s, then travels 60 m south in 15 s, all along a straight north-south road. What is the cyclist's average velocity for the entire trip?
A disk initially at rest is given a constant angular acceleration of 2.0 rad/s². Through what angle (in radians) has the disk turned after 5.0 s?
Two simple pendulums have exactly the same length and swing with the same small amplitude, but pendulum X has twice the mass of pendulum Y. How do their periods compare?
A solid uniform disk of mass 4.0 kg and radius 0.25 m spins about its central axis at 12 rad/s. The moment of inertia of a solid disk about this axis is I = ½MR². What is the disk's rotational kinetic energy?
A crate sitting on a level floor has a weight of 100 N. A person presses straight down on the top of the crate with an additional force of 30 N. What is the magnitude of the normal force the floor exerts on the crate?
A hiker walks 300 m due east and then 400 m due west along a straight, level trail. What is the magnitude and direction of the hiker's displacement for the whole walk?
A worker pulls a sled a horizontal distance of 8.0 m by applying a constant 50 N force directed 30° above the horizontal. How much work does the worker's force do on the sled?
A block of mass m₁ = 3.0 kg rests on a horizontal tabletop. A light, inextensible string runs horizontally from the block, passes over an ideal frictionless pulley at the edge of the table, and connects to a second block of mass m₂ = 2.0 kg that hangs freely. The coefficient of kinetic friction between m₁ and the tabletop is μ = 0.25. The system is released from rest and the hanging block descends. Use g = 9.8 m/s².
(a) In words, describe the free-body diagram for each block, naming every force that acts on it and its direction.
(b) Starting from Newton's second law applied to each block, derive a symbolic expression for the magnitude of the acceleration a of the system in terms of m₁, m₂, μ, and g.
(c) Calculate the numerical value of a.
(d) Calculate the tension in the string.