Physics 50 example problems: Recent Episodes
Peter Beyersdorf
This is a video podcast of solutions to example problems from Dr. Beyersdorf's Physics 50 class at San Jose State University. Several episodes will be published each week including solutions to the previous week's homework and examples that may be useful in understanding current homework or preparing for upcoming exams.
For a tube containing mercury and water, find the difference in height of the mercury and water using Pascal's law
Given some measurements of the pressure in a fluid taken on the surface of an unknown planet, use Pascal's law and the universal law of gravitation to find the mass of the planet.
Use Bernoulli's Equation to find the force on an airplane wing and then find the net force acting on the airplane.
For a block of wood floating on top of a layer of water and below a layer of oil, find its mass and density given how high it is floating
Determine the gauge pressure at a given distance below the surface of a fluid using Pascal's law
For a piece of cheese oscillating on the end of a spring, find out how far the spring will be stretched when the oscillations stop.
Find the gravitational force acting on the moon from the Earth and Sun for moon at three different points in the lunar orbit
Find the acceleration of a block on a plane that is attached to a rotating cylinder which has non-negligible moment of inertia
Find the frictional torque necessary to slow a spinning object a given amount in a given time
Solve for the speed of a falling block that must pull another block and spin a pulley that has inertia.
Relate the linear velocity of a car to the angular velocity of the axle as read by the speedometer
Use the parallel axis theorem to find the moment of inertia for a wheel rotating about a point on its rim.
Find the moment of inertia for a wagon wheel given the size and shape of its components.
Determine the linear acceleration of a point on the edge of a drill bit, given its angular velocity.
Relate the parameters of angular motion for a helicopter rotor blade to the parameters of linear motion for a point on the tip of the blade.
Calculate the change in the angular velocity and angular displacement of a flywheel that is slowing down due to friction
Relate an expression for the angular displacement of a merry-go-round to its angular velocity and angular acceleration
Find the speed of a bullet by using the work-energy theorem and conservation of momentum during a collision with a block
Find the angle of a ramp that causes a block sliding up the ramp to have the minimum speed after sliding a certain distance
Find the minimum height of a roller-coaster hill for the coaster to go over a loop successfully.
Find the speed a car was traveling given the length of the skid marks it left when it stopped.
Check if friction is a conservative force or not by determining the work it does when a book sliding on a table moves in a closed path
Find the initial speed and eventual height of a thrown rock using the work energy theorem
We look at the behavior of an elevator system known as Atwood's machine that consists of two masses held by a rope that goes over a pulley.
We find the acceleration of a pair of blocks that are connected to each other by a rope and a system of pulleys,
We find the maximum speed a stone can be swung at when it is on the end of a rope before that rope breaks
We find the acceleration of a block being pulled along a table by a rope and before and after a cat jumps onto the block
We draw the free body diagrams for two blocks on an incline connected by a rope over a pulley
Find the acceleration of an elevator necessary for a passenger to have an apparent weight that differs from her actual weight
A person is hanging from a rope, what is the tension in the rope as a function of the deflection angle
We look at how much a road must be banked for a car to accelerate around a turn without the aid of friction
Find the force responsible for accelerating a pendulum bob in an accelerating train car
Calculate the acceleration that the Earth feels due to the reaction force of the weight of a person.
Find the reaction forces for the forces that act on a woman in an accelerating elevator
Using information provided about the SAn Jose Grand Prix find the acceleration and other parameters for the race cars.
Use the equations of motion in 1 dimension to figure out how fast you need to run to catch a bus that is accelerating away from a nearby bus stop
USe the equations of motion in 1D to find the parameters of motion for a water balloon thrown from the roof of a building
USe the equations of motion in 1D to analyze the trajectory of a flea in free fall after jumping
Find the time to travel to the moon using some given values and the equations of motion in 1 dimension
The method for the solution to homework 1 is presented. A written solution and the full set of answers are available in a PDF document in the handouts podcast.
We practice unit conversion by finding the number of seconds in a year and then find the percent error in a simple estimate of this number
We show how to convert units from miles per hour to kilometers per hour and meters per second
We practice taking the cross product (also called the vector product) of vectors. We use both the method of the determinate and the right hand rule.
Problem 1.97 from the textbook - Given the location of two stars in the big dipper relative to the Earth, where would the Earth appear from the perspective of one of the stars?
We break a vector into its x and y components, then we consider an example where the components of the vector we are interested are inclined at an angle