Consider the following questions and a student's response to each question (shown in italics). In each case, determine if the student's answer is true or false.

Explain the reasons that the distance curve has the shape it does.

The distance curve is an increasing curved line because the object is accelerating.

TrueFalse    

The velocity curve is an increasing straight line. What does this mean?

The velocity curve is a straight line because the object is moving with constant speed.

TrueFalse    

Calculate the slope of the velocity curve. Do you recognize what this is?

The slope of the velocity curve is the acceleration of the object and I calculated a slope of about 4.9 m/s².

TrueFalse    

The acceleration curve is a horizontal straight line. What does this mean?

The acceleration curve is a horizontal line because the acceleration of the object does not change with time.

TrueFalse

Q2. A ball is released from the top of a cliff; it hits the ground 3.5 seconds later. Assuming the ball is a free falling object, how many meters is the cliff above the ground below? (Use

g = 9.8 m/s².

Express your answer to one decimal point.)

Q3. The velocity vs. time curve of an object is an increasing straight line. You observe that when the time is 1 second, the velocity is equal to 4 m/s, and when the time is 4 seconds, the velocity is 28 m/s.What is the acceleration of the object? (Express your answer to one decimal point.)

Q4. What is the magnitude of the acceleration of a modified Atwood machine if the mass of the cart is 8 kg and the hanging mass is 10 kg? (Use

g = 9.8 m/s².

Express your answer to one decimal point.

Q5 In a completely frictionless Newton's Cradle toy, the change in speed of the balls coming in and those going out is zero. This is because the net force at the time of the collisions is equal to the weight of the number of balls interacting.

TrueFalse

A charge 5.05 nC is placed at the origin of anxy-coordinate system, and a charge -1.97 nC is placed on the positive x-axis at x = 3.99 cm . A third particle, of charge 6.03 nC is now placed at the point x = 3.99 cm , y = 3.00 cm .

(1)Find the x-component of the total force exerted on the third charge by the other two.

(2)Find the y-component of the total force exerted on the third charge by the other two.

(3)Find the magnitude of the total force acting on the third charge.

(4Find the direction of the total force acting on the third charge.

Possible Duplicate:
Black hole formation as seen by a distant observer

Given that matter can never cross the event horizon of a black hole (from an external observer point of view), if a black hole is "fed" with a large amount of matter then the new matter will eventually become extremely compressed, and presumably would be compressed below its Schwarzchild radius.

Would secondary black holes eventually form near the original black hole?

As an alternative one could also imagine that the combined mass of the original black hole and the new mass around the event horizon becomes contained within the Schwarzchild radius of both masses, and so a new event horizon forms, "swallowing" the new mass around the edge of the original black hole.

This mechanism would allow black holes to swallow mass in a finite time.
Would this contradict GR predictions?

Four masses are at the corners of a square of length ℓ = 20.0 cm and a fifth mass is at the center of the square. The masses are m₁ = 5.00 g, m₂ = 3.00 g, m₃ = 1.00 g, m₄ = 5.00 g, and m₅ = 1.50 g.

a-Draw the free body diagram for fifth mass.

b-Determine the net gravitational force on the fifth mass in unit vector notation.

Answer the following questions about one-dimensional motion.

1. Imagine a fox darting around in the woods for several hours. Can the displacement △xof the fox from his initial position ever be larger than the total distance d he traveled? Explain.
2. What is the difference between acceleration and velocity? Write a paragraph that would make sense to a 5th grader.
3. Give an example of a situation where an object has an upward velocity, but a downward acceleration.
4. What is the difference between average and instantaneous velocity? Make up an example involving a trip in a car that demonstrates your point.
5. If the position of an object is increasing linearly with time (i.e., △x is proportional to t), what can we say about its acceleration? Explain your thinking.
6. If the position of an object is increasing non-linearly with time (i.e., △x is not proportional to t), what can we say about its velocity? Explain your thinking.

Part 1. A catcher “gives” with the ball when he catches a 0.113 kg baseball moving at 22.4 m/s.

If he moves his glove a distance of 6.1 cm, what is the average force acting on his hand?

Answer in units of kN.

Part 2.

Repeat for the case in which his glove and hand move 10.5 cm.

Answer in units of N.

A spherically-symmetric planet is made of an empty inner core of radius a surrounded by a thick shell of radius 2a, which is surrounded by another thick shell of radius 3a. The inner shell has a volume density that only depends on radius and is given by s1(r) = br^3, where b is a known positive constant. The outer shell also has a volume density that only depends on radius and is given by s2(r) = y/(r^2), where y is a known positive constant.

[Planet 2]

b=alpha

s= rho

y=gamma

Find the gravitational field in the following regions in terms of G, b, y, a, and r.

r < a:

a < r < 2a:

2a < r < 3a:

r > 3a:

A point charge with charge q1 = 3.50 μC is held stationary at the origin. A second point charge with charge q2 = -4.80 μC moves from the point ( 0.170 m , 0) to the point ( 0.255 m , 0.260 m ). How much work W is done by the electric force on the moving point charge?

Express your answer in joules. Use k = 8.99×10⁹ N⋅m^2/C^2 for Coulomb's constant: k=1/4πϵ0.

An atom of beryllium (m = 8.00 u) splits into two atoms of helium (m = 4.00 u) with the release of 92.2 keV of energy. Suppose the beryllium atom moved in the positive x direction and had a kinetic energy of 44.0 keV. One of the helium atoms is found to be moving in the positive x direction. Find the direction of motion of the second helium, and find the velocity of each of the two helium atoms. Solve this problem in two different ways: by direct application of conservation of momentum and energy; and by applying the results if the original beryllium atom is at rest to a frame of reference moving with the original beryllium atom and then switching to the reference frame in which the beryllium is moving.

(a) by direct application of conservation of momentum and energy

(b) by applying the results if the original beryllium atom is at rest to a frame of reference moving with the original beryllium atom and then switching to the reference frame in which the beryllium is moving

emergency physics question!

what is the minimum film of coating with index of refraction of 1.52 on a glass with index of refraction of 1.40 for which destructive interference of a red component of white light in air can take place by reflection? assume the wavelength of the red component in vacuum is 650nm. find the minimum visible wavelength in vacuum for constructive interference due reflection for the thickness of the coating film you found.

what should be the minimum additional coating to get constructive interference for the red component of 650nm?

not just an answer, I need help understand the answer and the question!

STEP BY STEP explanation please!

Compare and contrast spin recovery procedures for

Cessna 150 and

T-37 What makes the recoveries different for each aircraft?

Suppose astronomers were to discover a new comet at an aphelion of 40.0 AU, with a transverse velocity of v₀= 941 m/s

What

Halley's comet, which passes around the Sun every 76 years, has an elliptical orbit. When closest to the Sun (perihelion) it is at a distance of 8.823

Two stationary positive point charges, charge 1 of magnitude 3.85 nC and charge 2 of magnitude 2.00 nC , are separated by a distance of 43.0 cm . An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two charges.

What is the speed V_final of the electron when it is 10.0 cm from charge 1?

Express your answer in meters per second.

Please show your work!

Two point charges are arranged so there is a small distance between them. One charge is positive and the other is negative. If the two charges have different magnitudes, there is a spot (not at infinity) where the total electric field is zero.