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Please answer the questions below.
1. If you charge a pocekt comb by rubbing it with a silk scarf, how can you determine the sign of its charge?
2. Explain why fog or rain droplets tend to form around ions or electrons in the air.
3. Why does a plastic ruler that has been rubbed with a cloth have the ability to pick up small pieces of paper? Why is this difficult on a humid day?
4. The form of Coulomb's law is very similar to that for Newton's Universal Law of Gravitation. What are some similarities and differences between the two?
Please answer the questions below. Additionally, if you want to use this space to discuss the demo, please feel free.
1. If you charge a pocket comb by rubbing it with a silk scarf, how can you determine if the comb is positively or negatively charged?
2. Why does a shirt or blouse taken from a clothes dryer sometimes stick to your body?
Please answer the question by entering your response below.
Why are interference fringes noticible only for a thin film, like a soap bubble, and not for a thick piece of glass? Explain.
Please answer both of these questions below.
1) Suppose a thin piece of glass were placed in front of the lower slit in a double slit experiment so that the two waves enter the slits 180° out of phase. Describe in detail the interference pattern on the screen.
2) Since violet light is deviated through a greater angle than red light when both are incident at the same angle on a prism, is the index of refraction of glass for red light greater than or less than the index of refraction for violet light? Explain using the frequency or wavelength for each color.
Please answer the following question:
1) Why, in example 23-15 of the textbook (pg 711), must the converging lens have a shorter focal length than the diverging lens if the latter's focal length is determined by combining them?
To answer the question, see question 15 on pg 716 of your textbook, then respond to the question below.
How would the actual position of the fish differ from the apparent location of the fish in the diagram. Explain your answer.
Hi all,
I need someone from each group to post their group's choice of final project topic, and also to note what people are in your group. Remember that your choice of topics are:
1. Light as a particle
2. The Bohr model of the atom
3 . Nuclear Physics
Note that the group that chose to be a group of 5 will be the Bohr model group.
Respond to the blog by posting a message below.
A block-spring system undergoes simple harmonic motion with amplitude A. Does the total energy change if the mass is doubled by the amplitude remains the same? Do the potential and kinetic energies depend on the mass? Explain.
Respond to the blog by answering the question below. Then make a comment replying to at least 1 other student's response.
Consider a boat loaded with scrap iron blocks, floating in a swimming pool. If the iron in the boat is thrown overboard, will the water level in the pool sink, rise, or remain the same? Carefully consider Archimede's principle here.
Answer the questions by responding to the blog below, then respond to at least one other person's response.
A "Newton's Cradle" is a popular executive toy consisting of 5 pendula of equal mass and length that are touching when at rest, and so are free to swing back and forth and collide with each other. When one observes this device, you can see that when 2 balls are dropped from some height on 1 side, 2 balls always come back on the other side, so that momentum is conserved. However, momentum would also be conserved if when 2 balls made impact, a single ball came out on the other side at twice the speed. Why then doesn't this happen?
A bomb, initially at rest, explodes into several pieces. A) Is the linear momentum of the system conserved? B) Is the kinetic energy of the system conserved.
Answer the question below by responding to the blog.
A large bed sheet is held vertically by two students. A third student takes a raw egg and throws it as hard as he can at the sheet. Explain why the egg doesn't break when hitting the sheet, regardless of its initial speed.
Answer the questions below by posting a response to the blog .
A hill has height h. A child on a sled (total mass m) slides down starting from rest at the top. Does the velocity at the bottom depend on the angle of the hill if:
a) it is icy and there is no friction?
b) there is friction (deep snow)?
Two identical arrows, one with twice the speed of the other, are fired into an identical target. Assuming the hay exerts a constant frictional force on the arrows, how much farther will the faster arrow penetrate the target?
Why is it easier to climb a mountain via a zigzag trail than climbing straight up?
Please answer each question by posting a comment below.
2. Can a centripetal force ever do work on an object? Explain.
3. Can the normal force on an object ever do work? Explain.
25. Suppose you lift a suitcase from the floor to the table. Does the work you do on the suitcase depend on (a) whether you lift it straight up or along a more complicated path, (b) the time it takes, (c) the height of the table, and (d) the weight of the suitcase? Explain.
Please answer the question by responding to the prompt below.
On highways, racetracks, and exit ramps, civil engineers design turns that are "banked" (i.e pitched at an angle). Supposedly, designing the turns in this manner adds to the safety of the roads. In what way(s) is this possible? Explain your answer.
Please answer the question in the greatest possible detail.
An athlete grips a light rope that passes over a low-friction pulley attached to the ceiling of a gym. A sack of sand precisely equal in weight to the athlete is tied to the other end of the rope. The athlete climbs the rope, sometimes speeding up or slowing down as he does so. What happends to the sack of sand? Please discuss the motion of the athlete and the sack relative to both the ground and to the rope.
Please respond to the question below by posting an answer.
The force of gravity on a 2kg rock is twice as great as that on a 1 kg rock. Why then doesn't the heavier rock fall faster?
Hi all,
I couldn't upload the graphs themselves into this blog. However after plotting graphs of velocity vs time for 3 different rockets, I obtained accelerations of
313 m/s/s
170 m/s/s
337 m/s/s
There were a total of 5 rockets launched with different mixtures, which were:
1. 1/3 water
2. half full
3. 3/4 water
4. all air
5. way too overpowered
Discuss which ones you think match these accelerations and why. We will analyze in class tomorrow.
