True/False:

1. Gravity is an example of inverse square behavior.
2. A grindstone is rotating at constant rotational speed. There is a net torque on it.
3. A lever multiplies a force but does not redirect it.
4. On a rotating merry go round one child sits halfway out between the axis and the edge. Another child sits on the edge. Both kids have the same rotational speed.
5. Angular momentum is a vector.

If X, Y and Z are three arbitrary vectors, prove these identities:

a. (X×Y).Z = X.(Y×Z)

b. X×(Y×Z) = (X.Z)Y – (X.Y)Z

c. X.(Y×Z) = -Y.(X×Z)

How can a force (e.g., a muscle force or a gravitational force) produce a translatory and a linear force simultaneously?

1 .Identify type of image represented in the following graphic:

Group of answer choices

Real

Virtual

2. Identify type of image represented in the following graphic:

Group of answer choices

Virtual

Real

3. Identify the direction that the refracted beam will bend:

Group of answer choices

Towards the normal

Away from the normal

4. The capability of a prism that to separate white light into its constituent colors is due to the slight variation of index of refraction as a function of wavelength. This property is referred to as:

Group of answer choices

Dispersion

Funky Colors

Diffusion

Total internal Reflection

5. True or false: A ray of light within a medium of higher index of refraction comes to an interface with a medium of lower index of refraction at an angle greater than the critical angle. There is no light transmitted into the medium of lower index of refraction

Group of answer choices

True

False

6.You are standing exactly halfway between to perfectly parallel mirrors. You see your reflection in the mirror that you are facing, but you notice a second (and many more) reflection that appears even further away.   How much further away is the second reflection image from the first reflection image in the mirror you are facing.

Group of answer choices

10 feet from first reflection

• 1 Light year from first reflection

15 feet from first reflection

5 feet from first reflection

7.(True or false) Parallel rays that pass through a thin lens will be be directed through the lens focal point.

Group of answer choices

True

False

8.(True or false) The law of reflection is mathematically expressed with Snell's law: n 1 sin ⁡ θ 1 = n 2 sin ⁡ θ 2

Group of answer choices

True

False

Suppose a photon is absorbed by the electron in a hydrogen atom in an n= 2 state. What wavelength should the photon have to enable the electron to transition to the n= 4

state? Once the photon is absorbed, what are the various wavelengths of photons that could be emitted by the atom? (Use Bohr approximation).

A 54.0-kg woman stands at the western rim of a horizontal turntable having a moment of inertia of 490 kg · m² and a radius of 2.00 m. The turntable is initially at rest and is free to rotate about a frictionless, vertical axle through its center. The woman then starts walking around the rim clockwise (as viewed from above the system) at a constant speed of 1.50 m/s relative to the Earth. Consider the woman–turntable system as motion begins.

(a) Is the mechanical energy of the system constant?

Yes/No

(b) Is the momentum of the system constant?

Yes/No

(c) Is the angular momentum of the system constant?

Yes/No

(d) In what direction and with what angular speed does the turntable rotate?

Magnitude: ___ rad/s

Direction: Clockwise/Counterclockwise

(e) How much chemical energy does the woman's body convert into mechanical energy of the woman–turntable system as the woman sets herself and the turntable into motion?
___ J

A spherical shell is cut into two halves that remain forming the
sphere, but are electrically isolated from each other at a negligible distance. The nortern hemisphere is at potential +V_0 and the southern hemisphere is at potential -V_0. Obtain the potential V (r, θ, ϕ) inside and outside of the sphere.

Figure out

how to test what happens when the light rays come from underwater. Compare your ideas about why

things look different under water to how light rays appear to “bend.”.

Hydrogen is used in some semiconducting devices to improve their performance. Consider a material in which atomic hydrogen (H) diffuses at 1.8 × 10^-24 m²/s at 329 K.

1) When in use, the device is exposed to a large electric field. If the force on each charged hydrogen nucleus is 10 ^-11 N, use the fluctuation-dissipation relation to find out how fast they drift in the field at 329 K.

Is every galaxy in the universe rotating in the same way as our solar system?

An 82.0 kg skydiver jumps out of a balloon at an altitude of 1 100 m and opens the parachute at an altitude of 160 m.

(a) Assuming that the total retarding force on the diver is constant at 60.0 N with the parachute closed and constant at 3 600 N with the parachute open, what is the speed of the diver when he lands on the ground?

(b) Do you think the sky diver will be injured? Explain.

(c) At what height should the parachute be opened so that the final speed of the skydiver when he hits the ground is 5.00 m/s?m

(d) How realistic is the assumption that the total retarding force is constant? Explain your answer.

A pumpkin of mass 5kg shot out of a student-made cannon under air pressure at an elevation of 45 degrees fell at a distance 142m from the cannon. The students used light beams and photocells to measure the initial velocity of 54m/s. If the resistive force was F = -kmv^2, what was the value of k?

Electric charge can accumulate on an airplane in flight. You may have observed needle-shaped metal extensions on the wing tips and tail of an airplane. Their purpose is to allow charge to leak off before much of it accumulates. The electric field around the needle is much larger than the field around the body of the airplane and can become large enough to produce dielectric breakdown of the air, discharging the airplane. To model this process, assume that two charged spherical conductors are connected by a long conducting wire and a charge of 79.0 µC is placed on the combination. One sphere, representing the body of the airplane, has a radius of 6.00 m, and the other, representing the tip of the needle, has a radius of 2.00 cm.

(a) What is the electric potential of each sphere? r = 6.00 m: ]V

r = 2.00 cm: V

(b) What is the electric field at the surface of each sphere?

r = 6.00 m: magnitude____________ V/m? direction_________?

r = 2.00 cm: magnitude ____________ V/m? direction________?

Show that the charges placed on a system of fixed conductors are distributed on the conductors' surfaces in such a way that the electrostatic energy of the resulting field is a minimum (Thomson theorem)