PHYSICS HIGH SCHOOL

"One step in the manufacture of silicon wafers used in the microelectronics industry is the melt crystallization of silicon into a crystalline silicon ingot. This processis carried out within a special furnace. When the newly solidified ingot is removed from the furnace, it is assumed to have a uniform initial temperature of 1600 K, which is below the crystallization temperature. At this temperature, the thermal conductivity of silicon is 22 W/(m•K), the density is 2300 kg/m3, and the heat capacity is 1000 J/(kg•K). The hot solid silicon ingot is allowed to cool in air maintained at a constant ambient temperature of 30°C. The diameter of the silicon rod is 15 cm. End effects are considered negligible. The convective heat transfer coefficient is 147 W/(m2•K). What temperature will exist 1.5 cm from the surface of the ingot after a cooling time of 583 sec (9.72 min)?" Consider the rod as acylinder placed vertically.

Answers

Answer 1

Answer:

Answer:

fgfgfdgdg

Explanation:

gfdgfgfgd

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Are the objects described here in static equilibrium, dynamic equilibrium, or not in equilibrium at all? a. A girder is lifted at constant speed by a crane. b. A girder is lowered by a crane. It is slowing down. c. You're straining to hold a 200 lb barbell over your head. d. A jet plane has reached its cruising speed and altitude. e. A rock is falling into the Grand Canyon. f. A box in the back of a truck doesn't slide as the truck stops.
A 10-meter long ramp has a mechanical advantage of 5. What is the height of the ramp?
According to Ohm's law, what are the two variables that affect the amount of current in a circuit?
Which wave top or bottom has the larger frequency

Let's assume you use green light (λ = 550 nm) to look at an electron. What is the uncertainty in determining the electron's velocity? Express your answer rounded up to the nearest hundredth.

Answers

By uncertainty principle

λ = h / p.

Where λ = wavelength, h = Planck's constant = 6.63 * 10⁻³⁴ Js

λ = wavelength = 550 nm = 550 * 10⁻⁹ m, Mass of electron = 9.1 * 10 ⁻³¹ kg

p = Momentum = mv

λ = h / mv

v = h / mλ

v = 6.63 * 10⁻³⁴ / (9.1 * 10⁻³¹ * 550 * 10⁻⁹)

v = 1 324 675.325 m/s

v ≈ 1.325 *10⁶ m/s

How do you find an object's mass on an acceleration vs. force graph?

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Newton's 2nd law of motion is: Force= (mass) x (acceleration).

Divide each side by 'acceleration' and you have: Mass = (force) / (acceleration).

-- At any point on the graph, read off the force and the acceleration.
-- Divide the force by the acceleration.
-- The quotient is the mass.

It should be constant, unless the moving object is something like a rocket,
which is constantly burning fuel and reducing its mass.

a balloon is ascending at 3.0 m/s at a height of 20.0 m above ground when a package is released. the time taken, in the absence of air resistance, for the package to reach the ground is:

Answers

Answer:

Approximately $2.35\; {\rm s}$ , assuming that $g = 9.81\; {\rm m\cdot s^(-2)}$ .

Explanation:

Under the assumptions, the package would start with an initial upward velocity of $u = 3.0\; {\rm m\cdot s^(-1)}$ and accelerate downward at a constant $a = (-g) = (-9.81)\; {\rm m\cdot s^(-2)}$ (negative because acceleration points downward.)

Right before landing, the package would be $20.0\; {\rm m}$ below where it was released. Hence, the displacement of the package at that moment would be $x = (-20.0)\; {\rm m}$ (negative since this position is below the initial position.)

The duration of the motion can be found in the following steps:

Apply the SUVAT equation $v^(2) - u^(2) = 2\, a\, x$ to find velocity $v$ right before landing.
Divide the change in velocity $(v - u)$ by acceleration to find the duration of the motion.

Rearrange the SUVAT equation $v^(2) - u^(2) = 2\, a\, x$ to find $v$ , the velocity of the package right before reaching the ground. Notice that because the package would be travelling downward, the value of $v\!$ should be negative.

$\begin{aligned} v &= -\sqrt{u^(2) + 2\, a\, x} \n &= -\sqrt{(3.0)^(2) + 2\, (-9.81)\, (-20.0)}\; {\rm m} \n &\approx (-20.035)\; {\rm m}\end{aligned}$ .

Subtract the initial velocity from the new value to find the change in velocity. Divide this change in velocity by acceleration (rate of change in velocity) to find the duration of the motion:

$\begin{aligned}t &= (v - u)/(a) \n &\approx ((-20.035) - (3.0))/((-9.81))\; {\rm s} \n &\approx 2.35\; {\rm s}\end{aligned}$ .

Different _______ of light through two separate mediums causes the bending of wave fronts associated with light rays.

Answers

The different reflections of light through two separate mediums causes the bending of wave fronts associated with light rays. The reflection and refraction is caused by the medium associated with its light rays.

When Earth and the Moon are separated by adistance of 3.84 × 10^8 meters, the magnitude of
the gravitational force of attraction between
them is 2.0 × 10^20 newtons. What would be the
magnitude of this gravitational force of attraction
if Earth and the Moon were separated by a
distance of 1.92 × 10^8 meters?
(1) 5.0 × 10^19 N (3) 4.0 × 10^20 N
(2) 2.0 × 10^20 N (4) 8.0 × 10^20 N

Answers

Using the Universal Gratitation Law, we have:

$F= (MmG)/(d^2) \n MmG=2*10^(20)*(3.84*10^8)^2 \n MmG=29.4912*10^36$

Again applying the formula in the new situation, comes:

$F= (MmG)/(d^2) \n F= (29.4912*10^36)/((1.92*10^8)^2) \n \boxed {F=8*10^(20)}$

Number 4

If you notice any mistake in my english, please let me know, because i am not native.

The strength of the gravitational forces between two masses is
inversely proportional to the square of the distance between them.

So if you change the distance to

   (1.92 x 10⁸) / (3.84 x 10⁸) = 1/2

of what it is now, then you would change the force to

   1 / (1/2)² = 4

of what it is now.

   (4) x (2 x 10²⁰) = 8.0 x 10²⁰ newtons .

You're conducting a physics experiment on another planet. You drop a rock from a height of 2.3 m and it hits the ground 1.1 seconds later. What is the acceleration due to gravity on this planet?A. 4.2 m/s2
B. 3.8 m/s2
C. 2.4 m/s2
D. 9.8 m/s2