Please answer all parts of the problem

A person takes 15 minute showers in 100°F water using a 2.0 gallon per minute shower head. Ignoring losses, how many cubic feet of natural gas did the shower need if the house has a 40,000 BTU/hour water heater? The incoming water temperature is 50°F. Is it possible for this person to complete this shower without the water temperature dropping?

This is for an electric field mapping lab.

Show that electic field strength is equal to the potential gradient.

In some video games, spacecraft employ ion drives. Write a one page report discussing how an ion drive operates and whether it can efficiently propel a spacecraft. You will be marked on how well you explain scientific principles and the accuracy of your statements. Your report should be understandable by nonscientists.

Answer these and explain your reasoning.

1. How much energy would it take to remove the electron from unexcited hydrogen completely so that it is no longer bound to its proton?

2. Suppose a hydrogen atom in the n=3 state emitted light by decaying into the n=2 state. What color would that light be seen as? What about one starting at n=4 and ending in n=2? Can a hydrogen atom emit infrared light and end up in the n=2 state?

3.   If you can see light with wavelengths as short as 385 nm, how many lines of the Balmer series might you be able to see by eye with a bright light source and a spectrometer to make a spectrum?

4. Suppose that you could measure accurately the wavelengths of the first two lines of the Balmer series. How could you use those measurements to predict the wavelength of the first line of the Paschen series?

This is the method by which we can find the energy levels of atoms experimentally.

I have tried to answer the following questions. Please let me know if I missed one and why.

1) A light car and a heavy car are headed toward each other from opposite directions at the same speed. The ground is level. Which of the two will be harder to stop?

the heavier car

2)

The two cars move together in the direction of the larger car

3) You are standing on a skateboard on a level surface. Someone throws a ball to you along the direction the skateboard is pointing, and you catch it. In what direction do you move after catching the ball?

away from the ball's thrower

4) You are moving on a skateboard at constant speed towards a ball suspended from a very fine thread. When you reach the ball, you grab it and the thread breaks. What happens to your speed?

5)

It is about the same

6) You stand on a skateboard in the road with your board facing east. An 18-wheel truck from the west impacts with you without braking. How is the truck's speed affected by you?

The truck's speed is slightly less

7) Two trains of equal mass on the same track both travel east. Train A is in the lead and is moving quite slow. Train B is behind, but moving very quickly. When Train B catches Train A they stick, what do you think will happen?

They will move faster than train A but slower than B

A glass with a square cross section when viewed directly from above is filled with water. The glass is 8.0 cm wide on each side and is 17.6 cm high. (a) Find the net horizontal force exerted by the water on each side. (b) Find the net horizontal force exerted by the water on all four walls of the glass. (c) Find the net force exerted by the water on the bottom of the glass.

The thin uniform rod in the figure has length 5.0 m and can pivot about a horizontal, frictionless pin through one end. It is released from rest at angle θ = 50° above the horizontal. Use the principle of conservation of energy to determine the angular speed of the rod as it passes through the horizontal position. Assume free-fall acceleration to be equal to 9.83 m/s2.

Consider a charge of -1 nC at (-1,0) m, and a charge of +1 nC at (1,0). Calculate the electric potential everywhere in the plane.

The angle through which a rotating wheel has turned in time t is given by θ = a t− b t2+ c t4, where θ is in radians and t in seconds

PART A

If a = 9.0 rad/s , b = 15.5 rad/s2 , c = 1.6 rad/s4 , evaluate ω at t = 3.2 s .

Express your answer using two significant figures

PART B

Evaluate α at t = 3.2 s .

Express your answer using two significant figures.

PART C

What is the average angular velocity between t = 2.0 s and t =3.2 s ?

Express your answer using two significant figures

PART D

What is the average angular acceleration between t = 2.0 s and t =3.2 s ?

Express your answer using two significant figures.

Name and explain three ways in which momentum and kinetic energy are not conserved when they should be.

Two students are studying for their upcoming physics exam and discussing the differences between directed motion and random motion. While reviewing the students make the following comments:

Kenny: Directed motion and random motion are two separate things. In directed motion you can use Newton’s Laws to describe the motion of individual objects, but when objects exhibit random motion they are equally likely to move in any direction. For Newton’s laws to apply there must be net movement in a particular direction.

Jesse: I thought that the difference between random motion and directed motion was just a matter of how closely you examine what’s going on. Newton’s Laws still apply for objects undergoing random motion, but it would be really hard to work out all the details.

React to each student’s statement and discuss what you think about random motion. Do Newton’s Laws apply? Can you reconcile Kenny and Jesse’s statements? Note: This is an essay question. Your answer will be judged not solely on its correctness, but for its depth, coherence, and clarity.

1-what can you conclude about the energy of transformation and the conservation of mechanical energy for the motion of a pendulum'.?

Consider the earth moon system quantum mechanically! Treat the earth and moon as point masses.

1. Write down the potential energy function for the earth/moon. Compare it to the potential energy function for the hydrogen atom.
2. What is the “Bohr” radius for the earth/moon system?
3. Estimate the principle quantum number (n) of the earth/moon system.

A hollow spherical metal shell of density 6.90 g/cm³ floats almost completely submerged in water. If the outer diameter of the metal shell is 14.0 cm, what is the inner diameter?

A 2500 kg car encounters a banked, horizontal curve of diameter 240 m. The banking angle is 7.5 degrees, and the coefficient of friction between the tires and the road is 0.80. (a) What is the maximum safe speed of the car? (b) What is the net force on the car in this case?