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Classical Mechanics

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

Pulley

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?

Springs

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?

Kinematics: Motion Down and Incline

Do 12a and b. Well tell me how you figure out what vo is and the rest of the variables, the physics part, how you set the problem up, and do all the math and solve with an answer. Thanks.

Kinematics: A Rock Thrown Downwards

A rock is thrown straight downward with an initial speed of 3m/s into a well. As the same time, the bucket 110 meters down at the bottom of the well is raised at a speed of 2m/s. Determine how far the rock has fallen when it hits the bucket. (Use g = 10 m/s^2).

Pascal's Principle

The digging bucket on a large mechanical excavator is moved by a piston sliding within a single hydraulic cylinder. According to the manufacturer, the hydraulic fluid in the cylinder is pressurized to 1000 psi (6.895 x 10^6 Pa or 68 atm) by a pump. The cylinder has a diameter of 0.165 m and a stroke of 1.36 m. Determine the ma

Critical stress, stress field

Question 3 Tensile tests of an elastic material show that it has a Young's modulus of... Please see attached past exam questions

Poisson Ratio, Young's modulus

Please see attached past exam questions: (a) A material has a shear modulus of 4.615.... (b) Hence show that Young's modulus is...

Mechanics and Young's Modulus

For the cross-section of the following figure, which is made from material with Young's modulus 100MN/m^2: (a) State the location of the centroid. (b) Show that the second moments of area about the z axis and teh axis aa are respectively 2.51x10^5 mm^4 and 1.26x10^6 mm^4. (c) A strut is made of this section. When subject to

CT scanner

A CT scanner has to be able to form an image within a 40cm diameter image area. The spatial sampling along each profile is 1mm. What angular resolution (the angle between projections) is required to match this sampling distance at the boundary of the image area?

Tension on a bridge cable

A knight in armour on a horse leaves the castle. His squire has mistakenly lowered the drawbridge 20 degrees below the horizontal. The knight and his horse stop when their combined center of mass are 1 metre from the end of the bridge. The uniform bridge is 8 metres long and has a mass of 2000 kg. The lift cable is attached t

Hitting a Tennis Ball

The tennis ball has a horizontal speed of 15 m/s when struck by the racket. If it then travels away at an angle of 25 degrees from the horizontal and reaches a maximum altitude of 10m, measured from the height of the racket, determine the magnitude of the net impulse of the racket on the ball. The ball has a mass of 180g. Neglec

Loaded Sullivan's Perfect Ratchet

Show that in the case of zero external force the equation v=(fL/kT)^2 D/L (e^(fL/kT) - 1 - fL/kT)^-1 reduces to 2D/L. Then show that at high force (but still smaller than (epsilon/L)) the equation reduces to v=(fL/kT)^2 D/L (e^(-fL/kT)).