. Two-point charges are brought 0.01 m from each other. One has a charge of 10.0 nC, the other has a charge of -10.0 nC. What is the magnitude of the electrostatic force between them? Will they attract or repel each other? k = 9.0 x 109 N m2/C2

I keep getting a negative answer and it should be positive?

A person standing far away walks toward a plane mirror at a speed v, and the speed of the image is 2v relative to the person. Please compute the speed of the image relative to the person if the plane mirror is replaced by (a), a convex spherical mirror? (b), a concave spherical mirror?

Friction Experiment

Procedure:

1. On the pulley place 50 grams weight on the block which is 0.05kg
2. Attach the wood block using a string and hanger
3. Place the hanger on the other side of the pulley

Use additional weight and put them on the hanger in order to achieve a constant velocity

Data A:

Procedure:

1. Place 50 grams on top of the wood block and 50 grams on the hanger and observe acceleration. Use additional weight if necessary
2. Record the time for the motion
3. Calculate experimental acceleration
4. Calculate theoretical acceleration
5. Compare using percent error formula
6. Repeat one more time

Formulas A:

• M1= Mw+n*50 (n is an integer, start with n=1, go to n=4)
• N=M1 g
• Fnet= M2 g
• Mu= Fnet/N

Data B:

Formulas B:

• A(experiment)= 2d/t^2
• Average mu= 0.25 --> mu=0.25 for equation below
• A(theory)= (M2 g- mu M1 g)/(M1+M2)

Question: I'm looking for the formulas worked out for both data tables

ex: plugging in what numbers into what equation to get answers from both data tables?

A rocket ship is launched from rest from a space station. Its destinations 1.0 x 10^11 m away. The ship is programmed to accelerate at 7.4 m/s^2 for 12 hours. After 12 hours, the ship will travel at constant velocity until it comes within 1.0 x 10^10 m of its destination. Then, it will fire its retrorockets to land safely.

Event 1: t= , r= , v= ,

Event 2: t= , r= , v= ,

Event 3: t= , r= , v= ,

Event 4: t= , r= , v= ,

a(12)= , a(23)= , a(34)=

Mathematical Analysis?

A compost barrel can be considered as a solid cylinder of mass 50.0 kg and radius of r = 30.0 cm, and a length of 0.900 m. It can be turned about the long axis by applying a force to a handle located d = 20.0 cm from the axis of the cylinder. The compost barrel needs to be turned through 250 complete revolutions. Assume you can apply a constant force of F = 10.0 N (always perpendicular to the radius as the handle goes around in a circle).
What is the angular acceleration of the barrel?
How much time does it take to turn the barrel through 250 rev?
What is the angular velocity of the barrel at the end of that time? Is this reasonable?

An electron is confined inside a quantum dot, which for this question can be approximated as a one-dimensional quantum box with rigid walls. The ground state has an energy of 0.042 eV.

1. (a) In your own words, explain why the energy of the ground state of the system is larger than zero.

2. (b) Calculate the length of the quantum dot.

3. (c) What wavelength of photon is needed to cause a transition to the next excited state?

4. (d) Is the wavelength of 2.958 μm observed in the spectrum of the quantum dot? Explain your answer.

HI please answer these questions with clean handwriting.

• 1)What property of the spherical curve allows the vertex of positive and negative mirrors to be determined in the same way?

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• 2)What is an easy way to align the spherical mirror so that its center of curvature is on the optical axis (i.e., the centerline of the pinhole autocollimator beam)? Why is this a critical alignment?

In [ ]:

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• 3)What happens in the autocollimation measurement if the mirror's spherical center is slightly higher that the optical axis?

In [ ]:

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• 4) When measuring a concave mirror, what is a good choice for the focal length of the lens?

Lauren has a bow that can shoot arrows at speeds of 0.3c. She is travelling across the Great Sandy Desert to her next archery competition on an ultrafast train that moves at a speed of 0.5c. She has set up to practise on the train with a target that is 150 m away from her in the same direction that the train is travelling.

Greg is standing on a platform as the train travels by.

1. (a) What is the time between the events “Lauren shoots arrow” and “arrow hits target” for Lauren?

2. (b) How far is Lauren from the target as measured by Greg?

3. (c) When Lauren shoots an arrow, what is its speed as measured by Greg?

4. (d) Do either Greg or Lauren measure the proper time between the events described in (a)? Explain your answer.

5. (e) How long does it take for the arrow to reach the target as measured by Greg?

1. A mass of 0.019 kg attached to a spring with spring constant 27.0 N/m is pulled to the right 8.0 cm and released. The mass oscillates with a frequency of 6.0 Hz. If the mass is pulled to the right 16.0 cm before being released, what is the frequency?

a. 6.0 Hz

b. 3.0 Hz

c. 1.5 Hz

d. 12 Hz

e. 24 Hz

2. A window loses power/heat energy through a pane of glass to the cold outside. If the thickness of the glass is doubled and the area of the glass is halved, then the power loss to the cold outside will be?

a. one half of the original power loss

b. twice the original power loss

c. the same as the original power loss

d. four times the original power loss

e. one quarter of the original power loss

3. A skater spins on ice. When she pulls in her arms, she reduces her rotational inertia and her angular speed increases. Compared to her initial rotational kinetic energy, the rotational kinetic energy when she has pulled in her arms must be?

a. smaller

b. the same

c. larger

how do you linearize this data and what is the slope of the line?:

Distance of sphere's fall: .10m time .14 s

distance of sphere's fall: .50 m time .32s

distance of sphere's fall 1.00m time .46 s

distance of sphere's fall 1.7 m time .59 s

distance of sphere's fall 2.00 m time: .63 s

It's a top opening parabola

For a conservative force F, all if the following are correct except
A. there exists an associated potential energy function.
B. the line integral of F between points A and B by way of point C is independent of point C.
C. the line integral of F around a closed path is zero.
D. the line integral of F with limits A and B is independent of the order of the limits.
E. the force F must be the net force including the internal force.

Explain what would happen if we began Charge-to-Mass Ratio of Electrons experiment with a dot on the CRT (cathode-ray tube) screen instead of a line?

You are to fire a cannon and are trying to hit a target 300 meters due east of your current position. Your cannon fires projectiles with a mass of 2 kg and with an initial speed of 60 m/s. Gravity is pulling the projectile downward at an acceleration of 9.8 m/s2. There is a wind blowing from the north pushing the projectile southward with a force of 3 N. What is the angle θ up from the ground you must aim the cannon, and what is the angle φ the direction you must turn the cannon to the north? There is a large ridge between the cannon and the target, so your angle of inclination θ must be greater than 45 degrees. Use the acceleration vector given by the wind and gravity, the initial velocity, and the initial position (the origin), to find a position function for the projectile. This will depend on t, θ, and φ. Once you have this function, solve for t, θ, and φ.

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