Express the following quantities using the prefixes given in the
table. (Enter a numeric value between 0.1 and 100, and choose the
appropriate units.)
Power | Prefix | Abbreviation |
---|---|---|
10−24 | yocto | y |
10−21 | zepto | z |
10−18 | atto | a |
10−15 | femto | f |
10−12 | pico | p |
10−9 | nano | n |
10−6 | micro | µ |
10−3 | milli | m |
10−2 | centi | c |
10−1 | deci | d |
103 | kilo | k |
106 | mega | M |
109 | giga | G |
1012 | tera | T |
1015 | peta | P |
1018 | exa | E |
1021 | zetta | Z |
1024 | yotta | Y |
(a) 3 ✕ 1011 m
------ Select ------ yoctometers zeptometers attometers
femtometers picometers nanometers micrometers millimeters
centimeters decimeters dekameters kilometers megameters gigameters
terameters petameters exameters zettameters yottameters
(b) 6 ✕ 10-5 s
------ Select ------ yoctoseconds zeptoseconds
attoseconds femtoseconds picoseconds nanoseconds microseconds
milliseconds centiseconds deciseconds dekaseconds kiloseconds
megaseconds gigaseconds teraseconds petaseconds exaseconds
zettaseconds yottaseconds
(c) 4 ✕ 10-10 g
------ Select ------ yoctograms zeptograms attograms
femtograms picograms nanograms micrograms milligrams centigrams
decigrams dekagrams kilograms megagrams gigagrams teragrams
petagrams exagrams zettagrams yottagrams
In: Physics
In this module, you will look for an article or news story/video that relates to one or more of the following topics:
Conservative versus non-conservative forces
Potential Energy
Conservation of energy (as it relates to physics, not environmental friendliness)
These are pretty broad topics, but a few ideas should spring readily to mind.
By the end of the third day of the module, create a thread with a 250-word post including one or more of the topics listed above, an active hyperlink to your resource, a summary of the resource itself, a summary of the material you are learning in this module as it relates to your resource, and an explanation of how the topic or resource ties to your everyday life.
Question is not related to a lecture. Just requires an article, explanation of the article, and how Conservative versus non-conservative forces, Potential Energy, or Conservation of energy (as it relates to physics, not environmental friendliness) apply to that article.
In: Physics
A 28.0-kg block is connected to an empty 2.56-kgbucket by a cord running over a frictionless pulley. The coefficient of static friction between the table and the block is 0.41 and the coefficient of kinetic friction between the table and the block is 0.32. Sand is gradually added to the bucket until the system just begins to move. Ignore mass of cord. (Figure 1)
Calculate the mass of sand added to the bucket.
Calculate the acceleration of the system.
In: Physics
Calculate the number of free electrons per cubic centimeter (and per atom) for sodium from resistance data (relaxation time 3.1*10-14 s)
In: Physics
Rent a rideshare bike and ride it throughout the course at a
pace that elevates your heartbeat
somewhat, but without over-exertion. Time your ride and calculate
your average speed. Draw a
force diagram for the bicycle’s motion, and label it with estimates
of each force. Calculate the
power you used during your ride to maintain your average speed, in
watts and then in
horsepower. Calculate the (exercise) Calories you burned during
your ride. (My time was 8.23 minutes for 1.3 miles)
Rent a rideshare scooter and ride it throughout the same course
at a safe speed. Try to go
somewhat faster than the bike, but most importantly stay safe. Time
your ride and calculate your
average speed. Draw a force diagram and label it with estimates of
each force. Calculate the
power used by the electric motor to maintain your average speed, in
watts and then in
horsepower. (My time was 1.2 miles for 11minutes and 10mph.)
In both calculations, include estimates for resistance from both
surface friction and air. You will
need to research a plausible (e.g., order of magnitude) estimate
for (a) the coefficient of rolling
friction from the wheels (used in the same way as the coefficient
of kinetic friction we discuss in
class problems), and (b) drag from air resistance. Which is
larger?
MAke sure to calculate air resistance and friction resistance for the bike and scooter. Draw force diagrams for the bike and scooter.
In: Physics
What are Kepler’s Three Laws and why are they important?
In: Physics
Find out the magnitude as well as the direction of the following vectors:
Ax = 22.0 cm; Ay = 33.0 cm;
Bx = -11.0 m; By = 84.5 m;
Cx = -77.3 mm; Cy = -66.7 mm;
Dx = 34.5 m/s; Dy = -56.9 m/s.
In: Physics
A small mailbag is released from a helicopter that is descending steadily at 1.07 m/s.
(a) After 5.00 s, what is the speed of the mailbag?
v = _____ m/s
(b) How far is it below the helicopter?
d = _____ m
(c) What are your answers to parts (a) and (b) if the helicopter is
rising steadily at 1.07 m/s?
v = _____ m/s |
d = _____ m |
In: Physics
You have three 1.3 kΩ resistors.
A.) What is the value of the equivalent resistance for the three resistors connected in series?
B.) What is the value of the equivalent resistance for a combination of two resistors in series and the other resistor connected in parallel to this combination?
C.) What is the value of the equivalent resistance for a combination of two resistors in parallel and the other resistor connected in series to this combination?
D.) What is the value of the equivalent resistance for the three resistors connected in parallel?
In: Physics
Hands-on Lab: Air Resistance and Free Fall Name(s): Date: Please use a font color other than black, red or green for your answers. Theory: for several centuries, it was believed that heavy objects fall to the earth at a faster rate than lighter ones. Galileo (1564-1642) performed experiments to show that this was not true. He showed that it was possible for light objects to fall at the same rate as their heavy counterparts. Please watch the following videos for a review. https://www.youtube.com/watch?v=_Kv-U5tjNCY https://www.youtube.com/watch?v=feFw8Ygn3fk https://www.youtube.com/watch?v=aRhkQTQxm4w https://www.youtube.com/watch?v=_mCC-68LyZM We now know that in the absence of air resistance, all objects regardless of mass, size or shape, fall at the same rate when dropped from the same height. This was demonstrated on the Moon (where there is no atmosphere, and therefore no air resistance) by the Apollo 15 mission in 1971, as shown in this video: https://www.youtube.com/watch?v=ZVfhztmK9zI The air resistance an object encounters depends on the object’s surface area and its speed. The air resistance is directly proportional to the object’s surface area. As the object’s surface area increases, so does the air resistance it encounters. A light object with a large surface area such as a flat piece of paper will encounter significant air resistance as it falls. This air resistance is relatively large compared to the weight of the paper and will oppose the paper’s motion causing it to fall at a slower rate or with a smaller acceleration. If we were to somehow remove the air resistance the paper encounters (for example, by dropping it in a vacuum), then the paper would fall at the same rate as a heavier compact object such as a book. A heavier object with the same surface area as the paper, such as a book, on the other hand, will encounter a relatively small air resistance compared to its weight, and will fall at a faster rate or with a larger acceleration compared to the paper. In this lab, we will explore the above concepts. Materials needed: one sheet of letter-sized paper (8.5 x 11 inches), a heavy book of the same size, or a book and paper of matching size - that is having similar lengths and widths. Experiment 1: drop a sheet of paper and a book side by side from the same height at the same time. Important: ensure there are no strong air currents such as those produced by a fan or air conditioner while doing these experiments. Observe what you see and answer the following questions. Please select (highlight in a different color), the best answer from the choices provided. 1. In Experiment 1 we see that a) the sheet of paper falls at the same rate as the book and lands at exactly the same time the book does. b) the sheet of paper falls at a faster rate and hits the floor before the book does. c) the sheet of paper falls at a slower rate and hits the floor after the book does. d) the sheet of paper moves upwards towards the roof, while the heavier book falls straight down to the floor. 2. The observations in Experiment 1 can be best explained as follows: a) The air resistance felt by the paper is small compared to its weight, it therefore does not slow down as much. The air resistance felt by the book is large compared to its weight, it therefore slows down more than the paper and falls at a slower rate than the paper. b) Both the paper and the book feel the same amount of air resistance compared to their weights. Their motion is not affected by air resistance at all. That is why they both hit the floor at the same time. c) The paper is much lighter than the book. This causes the air to push upwards on the paper, and downwards on the book. Therefore, the paper and the book move in opposite directions d) The air resistance felt by the paper is large compared to its weight, this slows it down. The air resistance felt by the book is small compared to its weight, it therefore does not slow down as much. Therefore, the book hits the floor before the paper. Experiment 2: place the paper beneath the book (against the book’s lower surface) and drop the book and paper at the same time. Observe carefully, and answer the following questions. Please select (highlight in a different color), the best answer from the choices provided. 3. In Experiment 2 we see that a) the book pushes the paper out of the way and falls to the floor several seconds before the paper does. b) the paper and the book fall at the same rate and hit the floor at the same time. c) the paper accelerates to the floor at a much faster rate than the book, and falls several seconds earlier than the book. d) the paper accelerates to the floor at a much slower rate than the book, and falls several seconds after the book. 4. The observations in Experiment 2 can be best explained as follows: a) since the paper is below the book, it has a distance advantage over the book, it needs to travel a shorter distance to the floor than the book does. Therefore, the paper speeds up faster than the book, and hits the floor several seconds before the book does. b) the greater weight of the book pushes the paper out of the way, and the book falls straight down due to gravity due to its greater weight, while the much lighter paper remains floating in the air. c) the greater weight of the book pushes down on the paper, overcoming the air resistance in the path of the paper, and therefore allowing it to fall at the same rate. d) although the paper and book are released at the same time, the paper is lighter and therefore experiences a smaller gravitational acceleration. That is why the paper hits the floor several seconds after the book does. Experiment 3: drop the book and paper, but this time place the paper on top of the book. Observe carefully, and answer the following questions. Please select (highlight in a different color), the best answer from the choices provided. 5. In Experiment 3 we see that a) the paper being much lighter is left floating at the same place, the book accelerates downwards and hits the floor, while the paper remains floating hardly moving at all. b) the book accelerates to the floor at a much faster rate than the paper, and hits the floor several seconds earlier than the paper. d) the paper accelerates to the floor at a much faster rate than the book, and hits the floor several seconds earlier the book. d) the paper and the book fall at the same rate and hit the floor at the same time. 6. The observations in Experiment 3 can be best explained as follows: a) the paper is several times lighter than the book, therefore the acceleration due to gravity the paper experiences is several times greater than what the book experiences. Therefore, the paper hits the floor several seconds earlier than the book. b) the lightness of the paper enables it to float in the air, the book being much heavier is pulled down by the force of gravity immediately, thus the book falls while the paper floats. c) the book falls through the air before the paper and as it falls it clears the air resistance in the path of the paper, allowing the paper to fall at the same rate. d) the book is several times heavier than the paper, therefore the acceleration due to gravity the book experiences is several times greater than that what the paper experiences. Therefore, the books hits the floor several seconds earlier than the paper. Experiment 4: crumple the paper to make a compact ball or wad. Now hold the paper and the book side by side, and drop them both from the same height at the same time. Observe carefully, and answer the following questions. Please select (highlight in a different color), the best answer from the choices provided. 7. In Experiment 4 we see that a) the paper starts to spin while falling, this slows it down and it hits the floor several seconds after the book does. b) the paper and the book fall at the same rate and hit the floor at the same time. c) the book accelerates to the floor at a much faster rate than the paper, and hits the floor several seconds earlier than the paper. d) the paper accelerates to the floor at a much faster rate than the book, and hits the floor several seconds earlier the book. 8. The observations in Experiment 4 can be best explained as follows: a) the circular shape of the wad of paper creates an axis of rotation through its center. As it falls, the air pushes up on the paper causing it to rotate about this axis. This drains energy from the paper causing it to fall at a slower rate. Therefore, the paper hits the floor several seconds after the book. b) crumpling up the sheet of paper into a wad reduces its surface area. Due to its smaller surface area, the wad of paper experiences a much smaller air resistance. Since it has the same acceleration due to gravity as the book, it falls at the same rate as the book and hits the floor at the same time. c) the book is several times heavier than the paper, therefore the acceleration due to gravity the book experiences is several times greater than what the paper experiences. The shape of the paper has no effect at all, and thus the book hits the floor several seconds earlier than the paper. d) the paper is several times lighter than the book, and it is also now smaller in size than the book, therefore the acceleration due to gravity the paper experiences is several times greater than that which the book experiences. Therefore, the paper hits the floor several seconds earlier than the book. Multiple choice questions continued: Please select (highlight in a different color), the best answer from the choices provided. 9. From these experiments we can see that since the paper and book have different masses, a) the acceleration due to gravity that falling objects experience increases proportionally with mass. b) the acceleration due to gravity that falling objects experience decreases proportionally with mass. c) the acceleration due to gravity that falling objects experience increases with mass, but the increase is not proportional to the object’s mass, it is described by another more complicated equation. d) the acceleration due to gravity that falling objects experience does not depend on mass. 10. From these experiments we can see that a) lighter objects fall faster than heavier objects, regardless of how the objects are shaped. b) heavier objects fall faster than lighter objects, regardless of how the objects are shaped. c) in the absence of air resistance, all objects regardless of mass, shape and size, fall at the same rate. d) air resistance is so small in everyday life that it does not affect the motion of light objects such as sheets of paper or feathers and leaves when they fall down to the earth. Problem 1: a) An eagle with a mass of m = 7 kg while high up in the air, falls straight down vertically against an air resistance of R = 70 N. Find the acceleration of the eagle if the force of gravity pulling it down is equal to the air resistance R, in other words if mg = 70 N. (Note: please use g = 10 m/s2 in this problem). Hint: use the equation for Newton’s second law to find the acceleration: (for more information please see section 4.6 of your textbook) Net force = (mass)(acceleration) or in symbols: Fnet = ma We rearrange this equation to solve for the acceleration a: a = Fnet/m In this case if we take the downward direction as positive, then the force of gravity will have a positive sign and the air resistance which is acting upwards in the opposite direction to the force of gravity, will have a negative sign. In the above equation, Fnet is the sum of all forces acting on the object. In this problem, Fnet is the force of gravity (mg) minus the air resistance (R). We can write this in equation form as: Fnet = mg – R We substitute this term for Fnet in the above equation for the acceleration a, to get: a = (mg – R)/m Substitute the given values for all terms on the right hand side to find the acceleration a. Please show the values you substituted, your answer and the units for the answer. Answer: b) Based on your calculated value of the acceleration, what can you say about the speed of the eagle’s descent? Is the eagle moving at all? Justify your answer. Answer: Please enter the names of all group members at the top of this document. Each member of the group must submit a copy of the lab report through their individual eCampus account.
In: Physics
Paragraph 1- Outline a general definition and description of matter. Include descriptive features (as applicable) about the physics concepts – dependent factors, relevant terminology, conventions, common units of measure, etc.
Paragraph 2- Summarize one or more impacts of matter on aviation operations.
In: Physics
Physics/Neuroscience
Using complete sentences and proper vocabulary, describe (in your own words) how neural circuit for knee-jerk reflex works
In: Physics
Total mass (block plus masses) |
0.1029 kg |
0.1529 kg |
0.2529 kg |
0.302.9 kg |
0.3529 kg |
0.402.9 kg |
Normal Force |
1.01 N |
1.50 N |
2.48 N |
2.97 N |
3.46 N |
3.95 N |
fsmax |
0.06 * 9.8 = 0.588 N |
0.13 * 9.8= 1.27 N |
0.225 * 9.8 = 2.21 N |
0.305 * 9.8 = 2.99 N |
0.31 * 9.8 = 3.04 N |
0.38 * 9.8 = 3.72 N |
Mass of hanger plus masses |
0.06 kg |
0.13 kg |
0.225 kg |
0.305 kg |
0.31 kg |
0.38 kg |
From your measurements and analysis, and your understanding of the maximum static frictional force, can you come up with an equation that describes how fsmax depends on the normal force? Hint: Is fsmax proportional to the normal force? Is fsmax proportional to the normal force squared? etc.
What is the proportionality constant?
What are its units?
Does the proportionality constant make sense in terms of the materials of the block and horizontal surface? Explain.
In: Physics
The vector position of a 3.05 g particle moving in the xy plane varies in time according to r with arrow1 = 3i + 3j t + 2jt2 where t is in seconds and r with arrow is in centimeters. At the same time, the vector position of a 5.15 g particle varies as r with arrow2 = 3i − 2it2 − 6jt.
In: Physics
A daredevil college professor wants to jump across a canyon of depth 100m and width 50m on his motorcycle. He uses a ramp inclined at 60 degrees to cross the canyon.The other side of the canyon is 10m lower than his side. Find the Minimum velocity, vo, that his motorcycle should have to make it safely across the canyon. If he jumps with a velocity of vo/3 find out what (x,y) position he would crash
In: Physics