A 7.0-kg rock at a temperature of 30°C is dropped into a shallow lake at 30°C from a height of 1.0×10^5 m. What is the resulting change in entropy of the universe? (b) If the temperature of the rock is 100°C when it is dropped, what is the change of entropy of the universe? Assume that air friction is negligible (not a good assumption) and that c=860J/kg·K is the specific heat of the rock.

A certain refrigerator has a COP of 5.00. When the refrigerator is running, its power input is 500 W. A sample of water of mass 500 g and temperature 20.0 ºC is placed in the freezer compartment. How long does it take to freeze the water to ice at 0ºC?ANS = 83.3 s

I can't seem to get 83.3s

True or False

Determine if the following statements are true or false.

_____ 1. A liquid takes the volume of its container.

_____ 2. Particles of amorphous solids have no definite pattern.

_____ 3. A beef steak is an example of a crystalline solid.

_____ 4. Viscosity causes water to curve upward at the top rim of a glass.

_____ 5. There is more gas than any other state of matter in the universe.

_____ 6. All states of matter have a fixed mass and fixed volume.

_____ 7. The volume and shape of a solid can never change.

_____ 8. Surface tension explains why water forms droplets.

_____ 9. Water has greater viscosity than any other liquid.

_____ 10. A gas spreads out to fill all available space.

Matching

Match each definition with the correct term.

A 4.9-m-wide swimming pool is filled to the top. The bottom of the pool becomes completely shaded in the afternoon when the sun is 22 ∘ above the horizon.

Write a few lines about: Fluids, Density, Pressure, change of Pressure with Depth in a liquid (water) and Archimedes’ Principle. What the SI units on each of them and give some practical example of each of them.

A cement block accidentally falls from rest from the ledge of a 51.7-m-high building. When the block is 18.7 m above the ground, a man, 2.00 m tall, looks up and notices that the block is directly above him. How much time, at most, does the man have to get out of the way? Number Units

An object is 1.6 m to the left of a lens of focal length 0.6 m. A second lens of focal length -4 m is 0.58 m to the right of the first lens. Find the distance between the object and the final image formed by the second lens.

____ m

What is the overall magnification (with sign)?

Is the final image real or virtual?

Is it upright or inverted?

Two loudspeakers on a concert stage are vibrating in phase. A listener is 45.9 m from the left speaker and 34.7 m from the right one. The listener can respond to all frequencies from 20 to 20 000 Hz, and the speed of sound is 343 m/s. What is the lowest frequency that can be heard loudly due to constructive interference?

A proton is traveling horizontally to the right at 4.20×10⁶ m/s.

A) Find the magnitude of the weakest electric field that can bring the proton uniformly to rest over a distance of 3.50 cm. E=___ N/C

B) What is the direction of this electric field?

C) How much time does it take the proton to stop after entering the field? t=____ s

D) What minimum field magnitude would be needed to stop an electron under the conditions of part A? E=___ N/C

E) What is the direction of the field in part D?

If the coefficient of kinetic friction between tires and dry pavement is 0.90, what is the shortest distance in which you can stop an automobile by locking the brakes when traveling at 22.9m/s ?

On wet pavement, the coefficient of kinetic friction may be only 0.25. How fast should you drive on wet pavement in order to be able to stop in the same distance as in part A? (Note: Locking the brakes is notthe safest way to stop.)

If the coefficient of kinetic friction between tires and dry pavement is 0.90, what is the shortest distance in which you can stop an automobile by locking the brakes when traveling at 22.9m/s ?

Two asteroids of equal mass in the asteroid belt between Mars and Jupiter collide with a glancing blow. Asteroid A, which was initially traveling at vA1 = 40.0 m/s with respect to an inertial frame in which asteroid B was at rest, is deflected 30.0 ? from its original direction, while asteroid B travels at 45.0 ? to the original direction of A, as shown in (Figure 1).

a: Find the speed of asteroid A after the collision.

b: Find the speed of asteroid B after the collision.

c: What fraction of the original kinetic energy of asteroid A dissipates during this collision?

A tube 12 cm in diameter is carrying engine oil a distance of 4 meters from barrel to outlet. If the pressure difference between the ends of the tube is 1064.28 atm , what is the oil flow rate?

3.19 A gas with adiabatic exponent γ is compressed adiabatically from an initial state (Pi, Vi) to final state (Pf, Vf). (a) Show that the work done in this process is

W=((ViPi)/y-1)*[(Vi/Vf)^(y-1) -1]

(b) Evaluate the result numerically for one mole of helium gas initially
at P = 1.0 atm and T = 300 K compressed to half its initial volume.
(c) Compute the work done in an isothermal compression from the same
initial point to half the initial volume. Explain the difference between
the numerical results for work done in adiabatic and isothermal
compression.

A frictionless vertical post is inserted into a bowling ball with a hole drilled through its center. The ball has a mass of 10.5 kg. A rope is attached to a ring that has been affixed to the ball. Kurt pulls on the rope at an angle of 0 = 24.5° with respect to the vertical with a constant force of magnitude |F| = 134 N .

(a) How much work does Kurt do on the bowling ball by raising it through a vertical distance of 1.08 m at a constant velocity?

(b) How much work does the Earth do on the ball while it is being raised through a distance of 1.08 m?

(c) Kurt is lazy and would like to be able to raise the ball through the same vertical distance with a minimum effort. What two changes in his actions would you recommend to her?

(d) What is the net work done on the ball by the two forces acting on it?

(e) If Kurt raises the mass in a time of 0.56 s what is his horse power?