An object's weight is W0 on the earth.

a. What would be its weight (in terms of W0) if the earth had twice its present mass, but was the same size?

b.What would be its weight (in terms of W0) if the earth had half its present radius, but the same mass?

c. What would be its weight (in terms of W0) if the earth had half its present radius and half its present mass?

d.What would be its weight (in terms of W0) if the earth had twice its present radius and twice its present mass?

How can I find the force of a laser given wavelength and power? Is it just momentum or momentum multiplied by number of phtons or something else?

Problem 1: For all of the following problems, imagine a crane that is lifting a weight of mass m through a height h at constant speed, and consider the following three choices of system:

(1) system is the weight only; (2) system is the weight and the earth; (3) system is the crane only.

For each of these choices, and in this order, what is the net work done on the system by the external forces (Wext,sys) in the process considered?

(a) (1) 0; (2) mgh; (3) −mgh

(b) (1) mgh; (2) 0; (3) −mgh

(c) (1) −mgh; (2) mgh; (3) 0

(d) (1) 0; (2) mgh; (3) 0

Problem 2: For system (1) (weight only), which of the following is a correct statement of the energy changes going on inside the system during the process described?

(a) ∆Esource + ∆Ediss = −mgh

(b) ∆U G = mgh

(c) ∆K = 0

(d) ∆Ediss = mgh

Problem 3: For system (2) (weight and earth), which of the following is a correct statement of the energy changes going on inside the system during the process described?

(a) ∆Esource + ∆Ediss = −mgh

(b) ∆U G = mgh

(c) ∆K = 0

(d) ∆Ediss = mgh

Problem 4: For system (3) (crane only), which of the following is a correct statement of the energy changes going on inside the system during the process described?

(a) ∆Esource + ∆Ediss = −mgh

(b) ∆U G = mgh

(c) ∆K = 0

(d) ∆Ediss = mgh

Problem 5: If it takes a time ∆t to raise the weight through the height h, what is the power output of the crane for that process?

(a) mg (b) mgh (c) mgh/∆t (d) 0

A projectile is launched with speed v0 and angle θ. Derive an expression for the projectile's maximum height h.

A baseball is hit with a speed of 35.0 m/s . Calculate its height if it is hit at an angle of 30.0 ∘ .

A baseball is hit with a speed of 35.0 m/s . Calculate its distance traveled if it is hit at an angle of 30.0 ∘ .

A baseball is hit with a speed of 35.0 m/s . Calculate its height if it is hit at an angle of 45.0 ∘ .

A baseball is hit with a speed of 35.0 m/s . Calculate its distance traveled if it is hit at an angle of 45.0 ∘ .

A baseball is hit with a speed of 35.0 m/s . Calculate its height if it is hit at an angle of 60.0 ∘ .

A baseball is hit with a speed of 35.0 m/s . Calculate its distance traveled if it is hit at an angle of 60.0 ∘ .

A heat engine operates between two reservoirs at T2 = 600 K and T1 = 350 K. It takes in 1 000 J of energy from the higher-temperature reservoir and performs 250 J of work. Find (a) the entropy change of the Universe delta SU for this process and (b) the work W that could have been done by an ideal Carnot engine operating between these two reservoirs. (c) Show that the difference between the amounts of work done in parts (a) and (b) is T1 delta SU .

A particle undergoes a constant acceleration of 4.00 m/s2. After a certain amount of time, its velocity is 12.2 m/s. (Where applicable, indicate the direction with the sign of your answer.) (a) If its initial velocity is 6.1 m/s, what is its displacement during this time? m (b) What distance does it travel during this time? m (c) If its initial velocity is −6.1 m/s, what is its displacement during this time? m (d) What is the total distance the particle travels during the interval in part (c)? m

True or False

Heat Travels slower in air than in liquids or solids.

A metal sphere with radius ra is supported on an insulating stand at the center of a hollow, metal, spherical shell with radius rb. There is charge +q on the inner sphere and charge −q on the outer spherical shell. Take V to be zero when r is infinite.

Calculate the potential V(r) for r<r a .

Calculate the potential V(r) for ra<r<rb

Calculate the potential V(r) for r>rb

Find the potential of the inner sphere with respect to the outer.

Use the equation Er=−∂V∂r and the result from part (b) to find the electric field at any point between the spheres (ra<r<rb).

Use the equation Er=−∂V∂r and the result from part (c) to find the electric field at a point outside the larger sphere at a distance r from the center, where r>

A bicycle wheel has a diameter of 63.0 cm and a mass of 1.74 kg. Assume that the wheel is a hoop with all of the mass concentrated on the outside radius. The bicycle is placed on a stationary stand and a resistive force of 117 N is applied tangent to the rim of the tire.

(a) What force must be applied by a chain passing over a 8.99-cm-diameter sprocket in order to give the wheel an acceleration of 4.49 rad/s²?
N

(b) What force is required if you shift to a 5.70-cm-diameter sprocket?
kN

Captin Kirk has been forced to take the Enterprise to the center of the galaxy, which is approximately 26000 light-years from the Earth, but the warp drive is broken so that the ship will be limited to speeds loss than that of light.

1. what force would it take to accelerate such a mass at 1.0g(9.8m/s^2) to its final velocity , and how long would this take , starting from v=0?

2. what would the wavelength, frequency, and color of gamma-ray photons emitted by the ship headed back towards the Earth look like on Earth if emitted at a wavelength corresponding to the highest ever observed in real life for gamma rays in natural radiation?

3. If the Enterprise slows down to o.4c and fires torpedoes at 0.5c at a Klingon vessel approaching it at 0.3c then how fast are those torpedoes approaching the Klingons, from their perspective?

Body A in the figure weighs 92 N, and body B weighs 71 N. The coefficients of friction between A and the incline are μs = 0.51 and μk = 0.22. Angle θ is 39°. Let the positive direction of an x axis be up the incline. What is the acceleration of A if A is initially (a) at rest, (b) moving up the incline, and (c) moving down the incline?

You find a long spring and decide to create some standing waves. You note that the spring has an unstretched length of 2.0 m and a weight of 20.0 N. You anchor one end of the spring to a pold and stretch it to a length of 10.0 m. You shake the spring up and down with a period of .250 s, creating a standing wave with 4 antinodes. What is the horizontal force with which you are pulling the spring?

Attempt 4 A uniform, solid sphere of radius 5.50 cm and mass 1.25 kg starts with a purely translational speed of 3.25 m/s at the top of an inclined plane. The surface of the incline is 2.50 m long, and is tilted at an angle of 34.0∘ with respect to the horizontal. Assuming the sphere rolls without slipping down the incline, calculate the sphere's final translational speed ?2 at the bottom of the ramp.

A 1830-kg car experiences a combined force of air resistance and friction that has the same magnitude whether the car goes up or down a hill at 34.5 m/s. Going up a hill, the car's engine needs to produce 74.7 hp more power to sustain the constant velocity than it does going down the same hill. At what angle is the hill inclined above the horizontal?

1.Which of the following is a consequence of Special Relativity?

QUESTION 2

2.What is a possible application of the principle of equivalency from General Relativity?

QUESTION 3

If you could turn any of the planets in our solar system into a black hole, which would produce the black hole with the largest radius