Is work done when dragging a mass up a hill the same as the change in potential energy?

Is work the same as energy? I am confused as to why

The pV diagram in (Figure 1) shows a cycle of a heat engine that uses 0.250 mole of an ideal gas having γ=1.10. The curved part ab of the cycle is adiabatic. The internal energy of the gas changes by the following amounts: ΔUa→b=−2220J, ΔUb→c=−1.06×104J, and ΔUc→a=+1.29×104J. c=(0.002, 1.5) b=(0.009, 1.5)

Part A: Find the pressure of the gas at point a.

Express answers in pascals to three significant figures.

Part B: How much heat enters this gas per cycle?

Express your answer in joules to three significant figures.

Part D: How much heat leaves this gas in a cycle?

Express your answer in joules to three significant figures.

Part F: How much work does this engine do in a cycle?

Express your answer in joules to three significant figures.

What is the effective dose from 0.050 Ci of 210₈₄Po that is ingested that is ingested by a 70 kg person? Assume an exposure time of 24 hours. 210₈₄Po decays to the stable isotope 206₈₂Pb by alpha emission. Since the exposure is much shorter than the half-life, you can assume that the activity remains constant. Alpha particles have an RBE of 20.

A chunk of brass with mass 0.6 kg, with specific heat 380 J/(kg· K), and with temperature 400 K is placed in 0.6 kg of water, with specific heat 4186 J/(kg· K), and with temperature 280 K. The water and the brass are in an insulated container and come to thermal equilibrium. Find the final temperature in kelvins (closest answer).

AND

The asteroid Oumuamua observed this year in November traveled around the sun at a speed of 87,500 m/s. Its proper length is 180 m. How much does a stationary observer near the sun measure its length to be changed at this speed due to relativity? A positive answer means its length is measured to be increased and a negative answer means that its length is measured to be decreased. (In micrometers, closest answer.)

AND

A radioactive sample is measured to be emitting 200 alpha particles per second. 20 minutes later it is emitting only 126 alpha particles per second. The half life of the unstable nucleus that is emitting these particles is - (in minutes, closest answer)

Two point charges are placed on the x axis as follows: Charge q1 = 4.00nC is located at x = 0.200m , and charge q2 = 5.00nC is at x=?0.300m. What are the magnitude and direction of the net force exerted by these two charges on a negative point charge q3 = -0.600nC placed at the origin?

A. magnitude

B. direction

Find the moment of inertia of a circular disk of radius R and mass M that rotates on an axis passing through its center. [Answer: ½ MR2]
Step 1: Pictorial representation: Sketch a neat picture to represent the situation.

Step 2: Physical representation: 1) Cut the disk into many small rings as it has the circular symmetry. 2) Set up your coordinate system and choose its origin at the pivot point (or the axle location) for convenience. Then choose a not-special piece as a representative of those small masses dm:



Step 3: Determine the moment of inertia of this representative small mass and evaluate the integral for the total moment of inertia:










Step 4: Use the parallel-axis theorem to determine the moment of inertia of the disk around an axis located at the edge of the disk. Then compare the two moments of inertia and explain how the results make sense to you.

Why hʋ is greater than energy gap in some material and µe usually greater than µh (µe is electron mobility , µh mobility of holes)?

True or False. Please explain answer.

a) In the absence of net external force, the center of mass of a system remains at a fixed location.

b) Total mechanical energy can be a negative quantity.

Answer True or False for each question. For the three questions indicated also provide a full explanation; this is likely to take at least two sentences.

5) It will be possible to measure all properties of a particle with perfect accuracy if our technology increases.

6) By t = 1 sec, the U contained about 25 % He nuclei and the rest H nuclei . Explain.

7) In quantum physics, Heisenberg's uncertainty principle says that matter and antimatter can appear spontaneously in empty space. Explain.

8) Our U contains mass because for every 10⁹ matter particles it created it also created 10⁹+ 1 antimatter particles. Explain.

Ernest Rutherford (the first New Zealander to be awarded the Nobel Prize in Chemistry) demonstrated that nuclei were very small and dense by scattering helium-4 nuclei (⁴He) from gold-197 nuclei (¹⁹⁷Au). The energy of the incoming helium nucleus was 7.39 ✕ 10⁻¹³ J, and the masses of the helium and gold nuclei were 6.68 ✕ 10⁻²⁷ kg and 3.29 ✕ 10⁻²⁵ kg, respectively (note that their mass ratio is 4 to 197). (Assume that the helium nucleus travels in the +x direction before the collision.)

(a)

If a helium nucleus scatters to an angle of 102° during an elastic collision with a gold nucleus, calculate the helium nucleus' final speed (in m/s) and the final velocity (magnitude in m/s and direction counterclockwise from the +x-axis) of the gold nucleus.

⁴He speed m/s?

¹⁹⁷Au velocity m/s?

¹⁹⁷Au direction ° counterclockwise from the +x-axis?

(b)

What is the final kinetic energy (in J) of the helium nucleus?

J?

3.10 Show that the minimum cation-to-anion radius ratio for a coordination number of 4 is 0.225.
3.12 On the basis of ionic charge and ionic radii, predict crystal structures for the following materials: (a) CaO (b) KBr. Justify your selections.

A wheel is rotating about an axis that is in the z-direction. The angular velocity ωz is -6.00 rad/s at t = 0, increases linearly with time, and is +4.00 rad/s at t = 19.0 s . We have taken counterclockwise rotation to be positive.

How long is the time interval during which the speed of the wheel is increasing?

A muon is created 50 km above the surface of the earth. In the earth's frame, the muon is traveling directly downward at 0.9999c.

Part A

In the earth's frame of reference, how much time elapses between the muon's creation and the time it reaches the surface?

Part B

Use time dilation to determine, in the muon's frame, how much time elapses between the muon's creation and the time it reaches the surface.

Part C

In the muon's frame of reference, length contraction reduces the distance between the point at which it is created and the surface of the earth. What is this distance?