(a) How long (in s) would it take a 1.00 ✕ 10⁵ kg airplane with engines that produce of 100 MW of power to reach a speed of 200 m/s and an altitude of 12.0 km if air resistance were negligible?

_? s

(b) If it actually takes 950 s, what is the power applied, in megawatts?

_? MW

(c) Given this power, what is the average force (in kN) of air resistance if the airplane takes 1200 s? (Hint: You must find the distance the plane travels in 1200 s assuming constant acceleration.)

_? kN

Suppose that two blocks are positioned on an Atwood machine so that the block on the right of mass m1 hangs at a lower elevation than the block on the left of mass m2. Both blocks are at rest. Based on this observation, what can you conclude? A) m1>m2 B) m1<m2 C) m1=m2 D) You cannot conclude anything with the given information.

1.A particular material has a workfunction of (15.2 + A)/10 eV. Find the maximum wavelength of electromagnetic radiation that will result in the emission of photoelectrons from this surface. Give your answer in nanometers (nm) and with 3 significant figures. A: 19

2.Imagine the energy levels in an atom are given by E_n = - (8.30+A)eV/n². Find the wavelength of the photon emitted when an electron goes from n = (2+B) to n = 1. Give your answer in nanometers (nm) and with 3 significant figures. A:4 B:5

3. In the Bohr model for hydrogen, the energy levels are given by E_n = (-13.6eV) / n². Find the energy of a photon emitted when an electron in a hydrogen atom jumps from n = (A+3) to n = 2.

Calculate the answer in eV and make sure to include the unit. Report your final answer with three significant figures. A: 5

4. In an atom, an electron is jumping from state with an energy of –(2.45+(A/100)) eV to a state with an energy of –(5.24+(B/100)) eV. Find the wavelength of the emitted photon.

Give your answer in nm and make sure to include the unit. Report your final answer with three significant figures. A:54 B:11

Theory

a) How can you move a spacecraft just with solar radiation?

b) Explain how nanoparticle sunscreens can be transparent to the human eye, but still protect the skin.

c) What are the two main ways that nanoparticle sunscreens containing TiO2 or ZnO can protect your skin from ultraviolet radiation? [Note: the UV wavelengths of most concern are labelled UV-A (400-315nm) and UV-B (315-280nm)].

d) What is the largest size of TiO2 nanoparticle that could be used to make a transparent sunscreen (before to apply it)? [Hint: use the size parameter and wavelength of 500 nm]

e) What other factors would you need to consider before reducing the particle size to make a sunscreen transparent?

f) What colour would be the sky at noon (assuming normal incidence of the sun rays) if the atmosphere was made by 10 um particles?

g) Explain why is possible to do sensing with plasmonic nanoparticles.

h) Explain the working principle of a microwave oven. Would it still work if you doubled the wavelength of the exciting radiation?

i) Is it possible to detect spherical particles in air with a diameter of 1nm with the IR light? Comment the answer.

j) Is the Rayleigh scattering at λ=400 nm greater or smaller than the one at λ=700 nm for equal incident intensity of light? Explain the answer.

You and your friend Peter are putting new shingles on a roof pitched at 23 ∘ . You're sitting on the very top of the roof when Peter, who is at the edge of the roof directly below you, 5.0 m away, asks you for the box of nails. Rather than carry the 2.5 kg box of nails down to Peter, you decide to give the box a push and have it slide down to him.

If the coefficient of kinetic friction between the box and the roof is 0.55, with what speed should you push the box to have it gently come to rest right at the edge of the roof?

Two carts on an air track have the same mass and speed and are traveling towards each other. If they collide and stick together, find (a) the total momentum and (b) total kinetic energy of the system. (c) Describe a different colliding system with this same final momentum and kinetic energy.

Two billiard balls with the same mass m move in the direction of one another. Ball one travels in the positive x-direction with a speed of V1i, and ball two travels in the negative x-direction with a speed of V2i. The two balls collide elastically, and both balls change direction after collision. If the initial speeds of the balls were v1i=2.0m/s and v2i =1.0m/s, what would be the final speed and direction of ball two, v2f, in m/s?    Thank you so much.

Phys1011: Waves on a String and Frequencies of Tones and Voice The purpose of this lab is to examine properties of waves and become familiar with terms used in describing waves. Simulator questions are adapted from PhET contributors Trish Loeblein and Susie Dykstra. Part 1 – PhET Waves on a String simulator: Watch the lab video. Open Waves on a String (https://phet.colorado.edu/sims/html/wave-on-a-string/latest/wave-on-a-string_en.html). Investigate wave behavior using the simulation for a few minutes. For these lab exercises, set up the sim for a sine wave by selecting “No End” and adjusting “Damping” to “None”. Select ‘Oscillate. 2. Write a hypothesis about the relationship between a wave variable in the simulator and its effect on wave speed (amplitude, frequency, tension). Test your wave speed hypotheses, and determine the relationships between the wave variables and wave speed. Make claims about the relationships (direct, inverse, none) between wave variables, using evidence to support claims, and explaining the relationship between the claim and evidence. 3. Frequency and wavelength are both in your equation for speed. Why is it that, when you changed the frequency, you did not change the speed of the wave? 4. The only variable we found that affects the speed of a wave on a string was the tension of the string. How does this relate to how a musician tunes a stringed instrument? 5. How does increasing damping change the wave?

You are working in the cancer therapy division of a hospital. This hospital treats cancer by hitting a tumor with high energy protons from a cyclotron. When the protons leave the cyclotron they are going at half the speed of light. You are in charge of deflecting the protons so they hit the patent's tumor. This deflection is accomplished by passing the proton beam between two flat, parallel electrodes that have a length of 10.0 feet in the entering beam direction. The protons enter the region between the electrodes going parallel to their surface. The two electrodes are separated by 1.5 inches. A high voltage is applied to the electrodes so that the protons passing between them have a constant acceleration as they are attracted directly toward one plate and repelled by the other. After the protons leave the region between the plates, they are no longer accelerated during the remaining 200 feet to the patient. To set the correct high voltage, you need to calculate the magnitude of the acceleration the protons need when they are between the plates so that they are deflected by 1.0 degree, the angle between the incident beam and the beam hitting the patient. The speed of light is 1.0 foot per nanosecond.

Please write legibly. Thank you.

1. Is the acceleration due to gravity a universal constant? Explain.

2. Is the acceleration due to gravity of objects affected by the Earth’s rotation? Explain.

A lens of focal length f₁ = +20 cm has an object positioned 50 cm in front of it. A second lens of focal length f₂= -15 cm is located 10 cm behind the first lens. a) Determine the two image positions for this combination of lenses. b) Is each image real or virtual, upright or inverted, and magnified or demagnified?

A student, starting from rest, slides down a water slide. On the way down, a kinetic frictional force (a nonconservative force) acts on her. The student has a mass of 77 kg, and the height of the water slide is 12.9 m. If the kinetic frictional force does -7.1 × 103 J of work, how fast is the student going at the bottom of the slide?

Select TWO analytical tool that uses electromagnetic waves to measure velocity. Explain how each tool uses electromagnetic waves to measure velocity. Describe the region of the electromagnetic spectrum that the tools you selected use. What properties distinguish each of these two regions of the spectrum from other regions?

The all-new iPhone Xs has a 2716mAh Li-ion battery. After a full charge, Sam used it for exactly a full day without recharging, leaving 15% battery in the phone. If the voltage of the battery is 3.8V, estimate (1) the average electric current (in Amperes), (2) the total amount of electric energy (in Joules), and (3) the average power (in Watts) that Sam’s iPhone Xs consumed during that day. This battery only has a mass of about 50 grams. As a comparison, search online and then estimate the amount of energy released by the explosion of 50 grams of TNT

In the figure here, a stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.5 kg, encounters a coefficient of kinetic friction μL = 0.43 and slides to a stop in distance dL = 0.38 m. Piece R encounters a coefficient of kinetic friction μR = 0.45 and slides to a stop in distance dR = 0.40 m. What was the mass of the block?