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Classical Mechanics

Coordinates of the Center of Mass

The coordinates of three particles are (5, 7), (0, 3), and (-1,-1). If the three particles have masses of 1.0 kg, 2.0 kg and 2.0 kg respectively, what are the coordinates of the center of mass?

Oscillation and Pendulum Motion

A mass on a string of unknown length oscillates as a pendulum with a period of 4.0 (s). Parts a to d are independent questions, each referring to the initial situation. What is the period if: a. The mass is doubled? in seconds b. The string length is doubled? in seconds c. The string length is halved? in seconds d. The ampli

A ball of mass 0.5 kg, initially at rest, acquires a speed of 4 m/s

(See attached file for full problem description) Please change the file extension to *.doc so that it can be open by Word. 15. A ball of mass 0.5 kg, initially at rest, acquires a speed of 4 m/s immediately after being kicked by a force of strength 20N... 16. A wooden block of mass M is moving at speed V in a straight l

Impulse with Constant Velocity

An 79.1 kg astronaut is working on the engines of his ship, which is drifting through space with a constant velocity. The astronaut, wishing to get a better view of the Universe, pushes against the ship and much later finds himself 30.4 m behind the ship. Without a thruster, the only way to return to the ship is to throw his 0.5

Mechanics and Projectile Motion

I need some help with these two mechanics questions: 1. A punter kicks a football at an angle of 33.1 degrees with the horizontal at an initial speed of 24.5 m/s. What distance (in meters) away should a punt returner position himself to catch the ball just before it strikes the ground? And to what vertical height (in meters) d

Force and Tension

A tightly stretched "high wire" is 42.8 m long. It sags 3.5 m when a 63.8 kg tightrope walker stands at its center. What is the tension in the wire?

Current, magnitude

A solenoid 12 cm long has a total of 10,000 turns of wire uniformly distributed along its length. It carries a current of 0.833 A and is filled with a ferromagnetic material with a permeability 700 times the permeability of free space What is the magnitude of B at the center?

Kinetic friction

If an object slides directly down an inclined place, at a constant velocity of 6 m/s, how large is the coefficient of kinetic friction if the plane make an angle of 25 degrees with the horizontal?

Finding Wavelength and Amplitude

A wave travels along a stretched rope. The vertical distance from crest to trough for this wave is 17 cm and the horizontal distance from crest to trough is 23 cm. What is (a) the wavelength and (b) the amplitude of this wave?

Solve: Distance and Time

Hi, I need some assistance with the following questions: Question: At the average rate of 15 m/s^2. How much time does it take for the complete increase in speed? a. 0.25 s b. 4.0 s c. 0.0577 s d. 17.3 s e. 8.0 s Question: A car traveling 20 m/s is able to stop in a distance d. Assuming the same braking force, what

A safe

A safe with a mass of 150kg is at rest on the floor. what is the minimum horizontal force needed to move the safe if the coefficent of static friction between the safe and the floor is 0.3? a.441n b. 51n c.501n d.41n

Simple Harmonic Motion.

I have to find the mass of an object. The problem is that my result is a negative one. The problem is as follows: A teacher demonstrates a harmonic motion with an object of mass m0, hung on a wire with constant k. A mass of 1,25g is added to the object, which results in a loss of 2.5% of the original frequency. What is the


What is a pulley? where is it used?

A spherical-shaped hollow

A spherical-shaped hollow steel shell, with a radius of 2.5m, containing some instruments, is lowered by a cable into a lake. The shell with its contents weighs 7.2 * 10^5 N on the deck of the ship from which it is being lowered. What is the tension in the cable when the sphere is completely immersed in water? a. 1.8 kg b. 2

Question about Solids and Elastic Moduli

A copper wire has a length of 5.0m and a diameter of 3.0 mm. Under what load will its length increase by 0.3 mm. (If you need Young's Modulus (Y) for copper it is 11 x 10^10N/m^2.)

Speed of a Rolling Hoop

A hoop of radius 0.5 m and a mass of 0.2kg is released from rest and allowed to roll down an inclined plane. How fast is it moving after being dropped from a vertical distance of 3m? a. 5.4 m/s b. 3.8 m/s c. 7.7 m/s d. 2.2 m/s

How long would it take a roofer to lift a load?

A roofer lifts supplies to a height of 20m with a hand-operated wench. How long would it take him to lift a 200-kg load, if the wench has an efficency of 90%, and the rate at which the wench can do work is .8hp?

Linear Momentum and Collisions

A 16 g rifle bullet traveling 150 m/s buries itself in a 4.0 kg pendulum hanging on a 3.3 m long string, which makes the pendulum swing upward in an arc. Determine the horizontal component of the pendulum's displacement.

Physics: Springs and Compression

1. A spring is compressed 10 cm by pushing a body against it. When released the spring pushes the body towards another identical spring. The body must slide over a rough floor in order to reach the second spring. When it makes contact the body compresses the opposite spring by 8 cm. Once again the body is forced back over the ro

Linear Momentum and a Jet Catapult on an Aircraft

A jet catapult on an aircraft carrier accelerates a 20000 kg plane uniformly from rest over a distance of 50.0 meters (for 2 seconds) to launch speed of 50 m/sec. What is the magnitude of the net force on the plane?

Determining if a Copper Bowl Will Float

A hemispherical copper bowl with an outer diameter of 10cm and wall thickness 1mm is placed in a large bath of water. Will it float? (See attachment for diagram.) If it does float, how far will the base of the bowl sink beneath the water surface? Note: Density of copper 8960 kgm-3 Finally, perform a 'back of the envelo

Finding the Center of Mass of a Rod

A 3.0 kg rod of length 5.0 m has at opposite ends point masses of 4.0 kg and 6.0 kg(a) Will the center of mass of this system be (1) nearer to the 4.0 kg mass, (2) nearer to the 6.0 kg mass, or (3) at the center of the rod? Why? (b) Where is the center of mass of the system?

Free Body Diagrams

Problem: 3 boxes side by side on a table. (regular size box, larger box, regular size box). The boxes are given a small steady push. Please draw a free body diagram for each box. I am confused as to the paralell friction. Also, why would the boxes not move at all if the push was too small?

Physics question: projectile motion

A soccer player kicks a ball at an intial speed of 11.0 m/s at an angle of 40.0 degrees to the ground. a) How far will the ball travel horizontally? b) How long is it in the air?


Question: When an object weighing 50 N is hung from a vertical spring, it stretches 20 cm. Calculate the spring's elastic constant. If the 50 N load were replaced with a 80 N weight, how far would the spring stretch?

Kinematics: Two Locomotives

Two locomotives approach each other on parallel tracks. Each has a speed of v = 80 km/h with respect to the ground. If they are initially d = 9.0 km apart, how long will it be before they reach each other?