1.Explain in a short paragraph what a heat engine is and what it does. Make sure your explanation includes: (a) what is the purpose of a heat engine, (b) what does a heat engine need to achieve that purpose, and (c) what limits how well a heat engine can achieve that purpose ("efficiency")?

2.The idea that evaporation is a cooling process is a familiar and intuitive one. What sounds counter-intuitive at first is this claim: "Boiling is a cooling process" (but hopefully the first two videos above have convinced you of the veracity of this claim). Explain how boiling is a cooling process. Make sure your explanation refers to latent heat (or "latent heat of vaporization", to be specific). What is the key difference between evaporation and boiling?

Consider a rocket that burns steadily. The higher pressure in the combustion chamber, the faster the propellant burns. Why is this? The relationship is such that the higher the pressure, the closer the gaseous flame is to the surface and the more effectively it can transfer heat back to the surface thereby gasifying the propellant quicker. The rate of gas generation, ?_? , can be described by the equation: ?_?=?_1 ?^?, where P is the pressure, and C1 and n are the constants for a given propellant with given exposed surface area.

The hot gas leaving the rocket must pass through the throat of the exhaust nozzle at sonic velocity.

▪The higher the pressure, the greater the density of this gas and the greater the rate of mass flow at sonic velocity. (The speed of sound in a gas is independent of pressure.) Accordingly, the rate of gas escape, ??r_e , is described by the equation: ??=?2?r_e=C_2 P where C2 is a constant, dependent on cross section area of the nozzle throat and on the velocity of sound in the combustion products.

▪What is the steady operating pressure of a solid-propellant rocket for the given values of the constants C1 , C2, and n? What values of n keep it stable?

PLEASE WRITE CLEARLY AND EXPLAIN WHY IS THE ANSWER THE WAY IT IS PLEASE THANK YOU

A 1.56 kg block is held in equilibrium on an incline of angle q = 53.0o by a horizontal force, F, applied in the direction shown in the figure below.

When traveling through mountains, most highways periodically have emergency escape ramps to allow large, heavy vehicles to stop safely, even when their brakes are not working properly. One such escape ramp is angled 13 ∘ above the horizontal. The brakes on one large truck (mass 1.4×10⁴ kg ) fail when driving at a speed of 80 miles per hour (35.75 m/s), and the driver makes use of the escape ramp.

Part A: What is the minimum length of ramp necessary for this truck to come to a stop? Assume negligible friction and air resistance forces.

Part B: If instead dissipative forces (friction and air resistance) provide a constant force of 60,000N parallel to the ramp, what is the minimum length of ramp necessary for this truck to come to a stop?

my answer for part A is 290 m, but I am unsure how to get the answer for part B. please help

The 2015 supermoon eclipse of the moon took place when the moon was at perigee.

(a) How much larger (as per cent) is the angular radius of the moon at perigee compared to apogee?

(b) The moon is drifting away from the Earth at a rate of 4 cm per year. How long will it take until we no longer see any total Solar eclipses at perigee? You may assume that the semi-major axis of the Earth-Sun system does not change over this period

Question 1:

A uniform disk with mass 35.4 kg and radius 0.240 m is pivoted at its center about a horizontal, frictionless axle that is stationary. The disk is initially at rest, and then a constant force 27.5 N is applied tangent to the rim of the disk.

Part A

What is the magnitude v of the tangential velocity of a point on the rim of the disk after the disk has turned through 0.260 revolution?

Part B

What is the magnitude a of the resultant acceleration of a point on the rim of the disk after the disk has turned through 0.260 revolution?

_____________________________

Question 2:

A woman with a mass of 55.0 kg is standing on the rim of a large disk that is rotating at an angular velocity of 0.540 rev/s about an axis through its center. The disk has a mass of 108 kg and a radius of 4.50 m .

Part A

Calculate the magnitude of the total angular momentum of the woman-plus-disk system. (Assume that you can treat the woman as a point.)

Please: Answer all of below &Clear and briefly answer & Clearly identifiable handwriting or computer typing

Please give arguments about what determines the width of a ferromagnetic domain
wall?

5 moles of a monoatomic ideal gas are contained adiabatically at 50 atm pressure and 300 K. The pressure is suddenly released to 10 atm, and the undergoes an irreversible expansion during which it performs 4000 joules of work. Show to the final temperature of the gas after the irreversible expansion is greater than that which the would attain if the expansion from 50 to 10 atm had been conducted reversibly. Calculate the entropy product as a result of the irreversible expansion. The constant-volume molar heat capacity of the Gas is C_v has a volume of 1.5 R.

A 0.01 m jalapeno seed is placed in front of two thin symmetrical coaxial lenses 1 and 2, with focal lengths f₁ = +24 cm and f₂ = +9 cm, respectively, and with lens separation L = 10 cm. The seed is 6 cm from lens 1. Where does the system of two lenses produce an image of the seed? What size does it appear to be? Describe the 3 aspects of the final image.

Can anyone explain all the answers?

1. A roller coaster car is on a track that forms a circular loop in the vertical plane.  Roller coaster car is moving with constant speed. If the car is to just maintain contact with track at the top of the loop, what is the normal force acting on this car at the lowest point of track?
   1. mg
   2. 2mg
   3. 3mg
   4. 0
2. Bucket of water is rotated on the rope in vertical plane. If the length of a rope is increased twice, to prevent water from spilling on the top point of trajectory, how should we change the minimum speed of rotation?

1. We should increase speed twice
2. We should decrease speed twice.
3. We should increase speed 2^1/2times.
4. We should decrease speed 2^1/2 times.
5. We should not change speed at all.

3. A coin is sitting on the edge of rotating turntables. Compare two turntables, A and B. They have the same radius (it means coin sits at the same distance from a center), but different surfaces. We measure the maximum frequency of revolutions for which coin does not slide off the turntables. For turntable A this frequency as twice as big as for turntable B. We can conclude that coefficient of static friction between coin and turntable A is:

1. ½ of coefficient between coin and turntable B
2. the same as for turntable B
3. twice as big as coefficient between coin and turntable B
4. 2^1/2greater than one for turntable B.
5. 4 times greater than for turntable B

4. The gravitational force attractive force between two masses, is F. If the masses are moved to half of their initial distance, what is the gravitational attractive force?
   1. F/4
   2. F/2
   3. 2F
   4. 4F
5. Two massive objects are fixed in their positions. The third object of mass m is placed between these two at the point where gravitational force due to two massive objects is equal 0. The third object is displaced  slightly towards one of massive objects. The total gravitational force on the third object is now:

1. Zero
2. Directed in the direction which depends on which out of two massive objects has greater mass.
3. Directed in the direction of displacement of the third object
4. Directed in the direction opposite to displacement of the third object.
5. Directed perpendicular to displacement of the third object.

An archer standing on a 15 degree slope shoots an arrow at an angle of 23 degrees above the horizontal. How far down the slope does the arrow hit if it is shot with a speed of 44 m/s from a height of 1.78 m above the ground?

subject: Rational equilibrium of Torques

How does the moment of inertia relate to the probability distributions? How do torques add and what is necessary to establish rational equilibrium?

Question 5

You visit the new Chaco Hotel rooftop bar in old town. You're taking pictures of the fabulous views using your new $1,000 phone. Oops! The phone slips out of your hands plummeting to the ground 60 feet below. Ignoring air resistance. how fast is your phone traveling by the time it hits the ground ? [ Hint: 1 meter = 3.28 feet ] ( Circle one answer)

A.) 19mph

B.) 42 mph

C.) 37mph

D.) 602 mph

I am doing test corrections for my physics exam I put C(37mph and that was incorrect. Can you please help with this question very confused about it.

To treat a burn on your hand, you decide to place an ice cube on the burned skin. The mass of the ice cube is 11.3 g, and its initial temperature is -14.4 °C. The water resulting from the melted ice reaches the temperature of your skin, 32.0 °C. How much heat is absorbed by the ice cube and resulting water? Assume that all the water remains in your hand. Answer ______J

Constants may be found here:

PLEASE ANSWER ALL NOT UNDERSTANDING

1.An unsuspecting bird is coasting along in an easterly direction at 3.00 mph when a strong wind from the south imparts a constant acceleration of 0.200 m/s2. If the wind\'s acceleration lasts for 3.20 s, find the magnitude r and direction θ (measured counterclockwise from the easterly direction) of the bird\'s displacement over this time interval. (HINT: assume the bird is originally travelling in the x direction and there are 1609 m in 1 mile.)

Now, assume the same bird is moving along again at 3.00 mph in an easterly direction but this time the acceleration given by the wind is at a 45.0 degree angle to the original direction of motion. If the magnitude of the acceleration is 0.500 m/s2, find the displacement vector , and the angle of the displacement, θ1. Enter the components of the vector and angle below. (Assume the time interval is still 3.20 s.)

2 .Volumetric expansion coefficients of simple materials are often well catalogued. However, the thermal expansion coefficient β of a human body is less well known. This could affect the human body\'s specific gravity and, therefore, measurements of its body/fat ratio. Suppose that a human body of weight w0 (on dry land) is placed on a scale while completely immersed in formaldehyde of temperature T1. Once the temperature increases by ΔT, the scale reading drops by Δw. Derive an expression for β in terms of ΔT, w0, and Δw by assuming that the ratio of the formaldehyde ρf and the initial density of the body ρb is R = ρf /ρb. Assume also that ρf does not change when heated.

If the body weighs 224.3 lb on dry land and his weight reading lowers by 0.237 lb when the formaldehyde is heated from 66.40oF to 88.60oF, calculate the coefficient of volume expansion of the body.* Assume R = 0.720.

* The coefficient β will likely vary widely from one human body to the next. The numerical value computed here should not be considered factual.

3. If 39.5 mol of an ideal gas occupies 89.5 L at 77.00 °C, what is the pressure of the gas?

4. How many moles of gas are in 17.5 L N2 at 25 °C and 125 kPa?

How many moles of gas are in 41.9 L O2 at 25 °C and 125 kPa?

5. A 2250-kg space station orbits Earth at an altitude of 495000 m. Find the magnitude of the force with which the space station attracts Earth. The mass and mean radius of Earth are 5.98 × 1024 kg and 6370000 m, respectively.