A machine part has the shape of a solid uniform sphere of mass 220 g and diameter 2.90 cm . It is spinning about a frictionless axle through its center, but at one point on its equator it is scraping against metal, resulting in a friction force of 0.0200 N at that point.

Part A

Find its angular acceleration. Let the direction the sphere is spinning be the positive sense of rotation.

Part B

How long will it take to decrease its rotational speed by 19.0 rad/s ?

Compare Einstein's, Classical and Debye's theories of heat capacity.

An otter jumps horizontally off a cliff with a speed of 2.72 m/s and lands in the water a horizontal distance of 4.67 m from the edge of the cliff. How high above the water did the otter jumps from?

_________ m

An 8-ton truck is initially going up a 20° ramp with a speed of 90 km/hr. The truck, then, brakes reaching a speed of 36 km/hr after 3 seconds. Assuming constant deceleration determine (a) the magnitude of the braking force, (b) the additional time required for the truck to stop. Neglect air resistance and rolling resistance

Explain the relationship between magnetism and current. How are magnets and electric charges similar? How are they different? What is something new you learned about electricity and magnetism?

An Atwood's machine consists of blocks of masses m₁ = 9.1 kg and m₂ = 20.0 kg attached by a cord running over a pulley as in the figure below. The pulley is a solid cylinder with mass M = 8.00 kg and radius r = 0.200 m. The block of mass m₂ is allowed to drop, and the cord turns the pulley without slipping.

a) Why must tension T2 be greater than T1

B) what is the acceleration of the system assuming there is no friction

C) Tension in T1=

Tension in T2=

Two blocks on a frictionless horizontal surface are on a collision course.One block with mass 0.25 kg moves at 1 m/s to the right collides with a 0.5 kg mass at rest and the two masses stick together. What is the final speed of the blocks after the collision?

          a) -0.33 m/s

          b) +0.33 m/s

          c) 3.27 m/s

          d) 0.67 m/s

          e) 0.25 m/s

QUESTION 2 The Doppler Effect may be used to determine the relative velocity of objects, such as cars on the highway, or stars in the galaxy. When the OBSERVED frequency appears to increase, relative to the source, this means ... ...

the source is moving AWAY FROM the observer.

... the source is moving at the same speed as the observer.

... the source is moving TOWARDS the observer.

... the source and the observer are motionless.

A block is placed on a frictionless ramp at a height of 13.5 m above the ground. Starting from rest, the block slides down the ramp. At the bottom of the ramp, the block slides onto a frictionless horizontal track without slowing down. At the end of the horizontal track, the block slides smoothly onto a second frictionless ramp. How far along the second ramp does the block travel before coming to a momentary stop, as measured along the incline of the ramp?

An electric heater is really just a resistor with a voltage across it. If you want to have 682 W of heat with a voltage V = 112 volts, what resistance (Ω) should the heater coil have?

The fact that BE/A is greatest for A near 60 implies that the range of the nuclear force is about the diameter of such nuclides.

(a) Calculate the diameter of an A = 60 nucleus.
________ fm
(b) Calculate BE/A for ⁵⁶Fe and ¹⁰²Ru. The first is one of the most tightly bound nuclides, while the second is larger and less tightly bound.
⁵⁶Fe
________ MeV
¹⁰²Ru
________ MeV

These are the answered multiple choice questions about the forces in the Student and Backpack problem. Make a clear diagram which properly identifies all of the forces acting on the student (you will also need a similar, separate, diagram for the backpack), and then making the proper arguments leading to the correct answer.

(a) Which is stronger force, the force on the student by the backpack or the force on the backpack by the student?

The two forces are equally strong by Newton's First Law.

(b) Which is the stronger force, the force on the backpack by the student or the weight of the backpack?

The two forces are equally strong by Newton's Third Law.

(c) Which is the stronger force, the force on the student by the backpack or the weight of the backpack?

The force on the student by the backpack is stronger.The two forces are equally strong by a combination of Newton's First Law and Newton's Third Law.

(d) What kind of force is the force on the student by the backpack?

An electromagnetic force.

(e) Which is the stronger force, the contact force on the student by the ground or the weight of the student?

The force on the student by the ground is stronger.

Elastic collisions are said to conserve the total kinetic energy, while inelastic collisions result in some loss of energy. Provide and describe a real-life example of each type. Indicate where you think the lost energy went to for your inelastic example.