(a) Suppose a meter stick made of steel and one made of invar are the same length at 0°C. What is their difference in length at 21.5°C? The coefficient of thermal expansion is 12 ✕ 10−6/°C for steel and 0.9 ✕ 10−6/°C for invar.

(b) Repeat the calculation for two 20.5-m-long surveyor's tapes.

Please answer for college physics discussion post. Please only type out the response as when writing it and uploading it is difficult to read. Thanks!

Respond to the following in detail:

• In your own words, explain angular momentum, moment of inertia, and torque. Also give examples.

1. White dwarfs are not included in the luminosity classification because they are:
a) no longer producing energy by nuclear reactions
b) too small
c) not yet active stars; they have not yet begun nuclear reactions
d) no longer radiating energy away

2. Absolute magnitude is defined as the apparent magnitude that a star would have if
a) it were located at exactly 10 pc from Earth
b) it were located at exactly 10 AU from Earth
c) all the energy from the star was concentrated in the visual region
d) it were located at exactly 10 ly from Earth

3. What is a dwarf star?
a) main-sequence star
b) a star that is significantly smaller than a giant or supergiant star
c) large, planetary object, such as Jupiter
d) a star of about the same size (diameter) as Earth

If a system feels any external force, must it then by necessity not satisfy conservation of momentum? What if it feels two such external forces that happen to balance? What if it feels two such external forces that happen to balance in just (say) the x-direction but do not balance in (say) the y-direction?

For a system that’s initially at rest (zero initial total momentum and zero initial kinetic energy) but then ends up with multiple objects moving (non-zero final total momentum and non-zero final kinetic energy), what would you have to do to use conservation of mechanical energy in order to determine info about the objects’ velocities?

A potential difference of 53 mV is developed across the ends of a 12.0-cm-long wire as it moves through a 0.27 T uniform magnetic field at a speed of 4.0 m/s. The magnetic field is perpendicular to the axis of the wire.

What is the angle between the magnetic field and the wire's velocity?

How are the properties of magnetic field lines similar to the properties of electric field lines?How are they different? (at least three for each) Thanks for your help.

Work on a sliding crate.

A worker pushes a 47.0 Kg crate across a level horizontal floor by applying a constant force of exactly 150.0 N at an angle of 23.0 degrees below the horizontal. The crate begins at rest and ends 15.0m from where it started traveling at 2.6m/s

A. What is the work done by the applied force as the crate moves across the floor?

B What is the work done by the friction force as the crate moves across the floor?

C. What is the coefficient of kinetic friction [Uk] between the crate and the horizontal plane?

The Tevatron at Fermilab is a cyclotron capable of producing a maximum energy of 2.0 TeV (2×1012eV). Its

circumference is 6.4 km. (a) How fast would proton be moving in the Tevatron? How large of a magnetic

field is required? (b) Repeat part (a) using electrons instead

of protons.

A series of object are being rotated. The same net torque is being applied to each object. Rank the object in order of the resulting angular acceleration (1=lowest).

( ) A solid disk spinning about its center. Total mass is 0.5M and the radius is 2R.

( )An object consisting of two objects connected by a massless rod. Each object has a mass of 2M and is a distance R from the axis of rotation.

( )A solid disk spinning about its center. Total mass is M and a radius of R.

( )A hoop spinning about its center. Total mass is 2M and a radius of R.

Serena's average serve is about 120 mph! Before you begin you will need to convert that to meters per second. It takes the eye about 100 milliseconds to tell the brain it's looking at the ball. By the time the opposing player is ready to react, she only has 400 milliseconds to do so.

1-According to the Sport Science Video on Serena's serve, how long does it take for the eye to pick up the ball once she hits the serve? Write the time in milliseconds.

2-The opponent to Serena's serve doesn't pick up the ball until it as at the net. How long do they have to react to the serve once it is at this point? Write your answer in milliseconds.

3-Serena's serve is clocked on average at 120 mph. Calculate the impulse (change in momentum) on the ball. Assuming its initial speed is zero m/s and the final speed is 120 mph. Let's change that to m/s. The mass of tennis ball is approximately 0.06 kg.

4-If Serena's racket is in contact with the ball for .005 seconds, what is the average force she hits the ball during her serve? This calculation is in Newtons.

5-What is the acceleration of the tennis ball? In m/s^2

Find the magnitude and direction of the resultant of two concurrent forces of 50 and 75 N acting on a body at angle of 50 degrees with each other Use the graphical method and the algerbraic method

For the two state paramagnet, explain why the magnetization M approaches zero at high temperatures.

Suppose the electric field between the electric plates in the mass spectrometer of Figure 27-33 in the textbook is 2.64×104 V/m and the magnetic fields are B=B′=0.36T. The source contains carbon isotopes of mass numbers 12, 13, and 14 from a long dead piece of a tree. (To estimate atomic masses, multiply by 1.66×10−27kg.)

How far apart are the lines formed by the singly charged ions of each type on the photographic film?

What if the ions were doubly charged?