1. A block of mass m₁ = 2kg is placed on a 30 degree incline. The block is attached to a string that passes over a pulley at the top of the incline. vertically from a string that passes over a pulley. A mass m₂ = 0.2kg is hanging from the other end of the string. If the coefficients of static and kinetic friction are u_s = 0.4 and u_k = 0.3,
   1. Will the system accelerate if it’s initially at rest? Justify your answer with physics!
   2. If it does accelerate, what is the acceleration? In which direction is this acceleration?
   3. What is the value of m₂ that will cause the system to be stationary if friction is negligble?

Which muscle has the biggest advantage? which one

Brachioradialis

Biceps

Brachialis

The cylinder in the figure(Figure 1) has a moveable piston attached to a spring. The cylinder's cross-section area is 10 cm2, it contains 0.0040mol of gas, and the spring constant is 1500 N/m. At 19 degreesC the spring is neither compressed nor stretched.

How far is the spring compressed if the gas temperature is raised to 200 degrees C ?

A package of dishes (mass 50.0 kg) sits on the flatbed of a pickup truck with an open tailgate. The coefficient of static friction between the package and the truck's flatbed is0.340, and the coefficient of kinetic friction is 0.180.

(a) The truck accelerates forward on level ground. What is the maximum acceleration the truck can have so that the package does not slide relative to the truck bed?

(b) The truck barely exceeds this acceleration and then moves with constant acceleration, with the package sliding along its bed. What is the acceleration of the package relative to the ground?

(c) The driver cleans up the fragments of dishes and starts over again with an identical package at rest in the truck. The truck accelerates up a hill inclined at 10.0

Collision derivation problem. A car is released from rest on a frictionless inclined plane (Figure 5.3). EXAMPLES: Calculate the momentum pi at the end of the plane in terms of the measured quantities x, y, L, and m. Assume is very small so that h/L is approximately equal to y/x. (Hint: use conservation of energy and the fact that K=1 2mv2=p2 2m.)
[Answer: .]
If a car suffers a nearly elastic collision it will coast back up the ramp a distance Lf before reversing direction. What is the momentum pf immediately following the collision? The general expression for the change in momentum suffered in a collision is is = - . What is p (the magnitude of ) in terms of x, y, Li, Lf, and m?
[Answer: .]
This is the expression you should use in the experiment. Make sure you understand how to derive these equations.
QUESTION:
If the car has a mass of 0.3 kg, the ratio of height to width of the ramp is 11/110, the initial displacement is 1.8 m, and the change in momentum is 0.62 kg*m/s, how far will it coast back up the ramp before changing directions?

A window washer weighing 788.3 N is standing on a scaffold supported by a vertical rope at each end. The scaffold weighs 294.9 N and is 5.486 m long. What is the force in each rope when the window washer stands 1.62 m from one end?  

What factors affect the resistance of conductor?

Three point charges are located at the corners of an equilateral triangle as in the figure below. Find the magnitude and direction of the net electric force on the 1.10 µC charge. (Let A = 1.10 µC, B = 6.80 µC, and C = −4.16 µC.) Three charged particles lie in the x y-coordinate plane at the vertices of an equilateral triangle with side length 0.500 m. Positive charge A is at the origin. Positive charge B is in the first quadrant, along a line 60.0° counterclockwise from the positive x-axis. Negative charge C is at (0.500, 0). magnitude N direction ° below the +x-axis

Copy and paste the following questions in the submit box below and find the location where the following information is found:

Give the line numbers where the hypothesis occurs.
Give the line numbers where the experiment is described.
Give the line numbers where the results are presented.
Do you see signs of pseudoscience in this article, if so, Give the line numbers. Briefly describe the graph:

1. 1 Pesticides suspected in mass die-off of bees Text excerpted from March 29, 2012|By Eryn Brown, Los Angeles Times

2. 2 Scientists have identified a new suspect in the mysterious die-off of bees in recent years � a class of

3. 3 pesticides that appear to be lethal in indirect ways. The chemicals, known as neonicotinoids, are designed

4. 4 to target a variety of sucking and chewing insects, including aphids and beetles. Bees are known to ingest

5. 5 the poison when they eat the pollen and nectar of treated plants, though in doses so tiny that it was not

6. 6 seen as a threat.

7. 7 A study published online Thursday by the journal Science indicate that the pesticides are not altogether

8. 8 benign. The study used miniature radio frequency chips to track honeybees and found that the pesticide

9. 9 impaired their ability to navigate back to the hive after a feeding expedition.

10. 10 Beekeepers became alarmed that honeybees were vanishing from their nests across the U.S. in the fall of

11. 11 2006 � victims of a perplexing and pervasive malady now known as colony collapse disorder that wiped

12. 12 out as many as 90% of bees, in some cases. Scientists don't know exactly why the ailment strikes, but

13. 13 they believe it results from a combination of habitat degradation, infection by pathogens and parasites and

14. 14 pesticide use. Researchers have also documented sharp declines in bumblebees, which are important crop

15. 15 pollinators but are not domesticated.

16. 16 Neonicotinoid pesticides were developed to eradicate insects without threatening mammals. The

17. 17 chemicals, which are incorporated into the tissues, leaves and flowers of plants, target the central nervous

18. 18 system, leading to paralysis and death. Farmers began using them in the early 1990s.

19. 19 Past studies have explored effects of neonicotinoids in the lab, finding that they might harm bees'

20. 20 memory, learning and orientation. But the new study is among the first to examine the pesticides' effects

21. 21 on bees under real-world conditions.

22. 22 The study led by researchers from the French National Institute for Agricultural Research, or INRA,

23. 23 focused on honeybees, which have been victimized by colony collapse disorder throughout the Northern

24. 24 Hemisphere.

25. 25 First they glued special radio frequency identification tags to the bees' thoraxes. Then they fed the bees

26. 26 sublethal doses of a neonicotinoid and monitored the insects as they attempted to return to the hive.

1. 27 The research team discovered that the "intoxicated" bees were about twice as likely as unexposed bees to

2. 28 die because they couldn't find their way home. Computer simulations suggested that these no-shows could

3. 29 cause hive populations to crash in a matter of weeks, said study coauthor Mickael Henry, a researcher at

4. 30 INRA in Avignon. The weakened colonies would be especially vulnerable to environmental

5. 31 stresses such as climate change or disease, he added.

32

1. 33 The new findings lend support to the notion that pesticides contribute to colony collapse, but

2. 34 leave open the likelihood that habitat destruction and illness play a role too, scientists said.

3. 35 "There are a whole lot of things that stress the honeybees," said Eric Mussen, a honeybee

4. 36 specialist at UC Davis. "You can't point your finger at one thing and say, 'That is the problem.' "

5. 37 Mussen cautioned against singling out neonicotinoids when other pesticides could have similar

6. 38 effects on bees. Besides, he said, many insects have built up immunity to neonicotinoids, so

7. 39 farmers are likely to switch to different pesticides anyway.

B: Bees released at a random location a kilometer away from the hive. Vertical axis shows relative number of bees returning to hive (1 = 100%)

Graph from: Henry, M., Beguin, M., Requier, F., Rollin, O., Odoux, J., Aupinel, P., Aptel, J., Tchamitchian, S., & Decourtye, A. (2012). A Common Pesticide Decreases Foraging Success and Survival in Honey Bees Science

I have three different homework questions I cannot seem to get
My hw is due at 12 so if anyone can help that would be helpful

Thank you

1)   For a car moving with speed v, the force of air drag is proportional to v². If the power output of the car's engine is quadrupled, by what factor does the speed of the car increase?

2)Tarzan

3) A wheel of mass 13 kg is pulled up a step by a horizontal rope as depicted in the figure below. If the height of the step is equal to one-fifth the radius of the wheel,

What is the maximum value of the electric field in an electromagnetic wave whose average intensity is 7.45 W/m2 ?

Four moles of a monatomic ideal gas are taken through a three-process thermodynamic cycle. The gas initially has a pressure of 8.00 atm with a temperature of 600 K (point A). The gas it then expanded isothermally to point B where the volume is 48.0 L. The gas is compressed via an isobarically process (point C). The gas is then expanded adiabatically back to its initial state. For all calculations using the ideal gas law assume that R = 0.08 (L atm) / (mol K). For any calculations of work, heat, internal energy, or entropy use R = 8.0 J / (mol K).

a. Compute all unknown pressures, temperatures, and volumes and organize them into a table.

b. Find the work done going from point C to point A?

c. What is the heat added to the system going from A to B?

d. What is the change in internal energy going from B to C?

e. What is the change in entropy going from A to B?

A very long conducting pipe (hollow cylinder) has inner radius a= 1.2 cm and outer radius b= 2 cm . It carries charge per unit length of + 530 nC/m . A line of charge lies along the axis of the pipe. The line of charge also has charge per unit length of + 530 nC/m .

A- What is the coefficient of 1/r in the correct expression for the electric field strength as a function of r for r < a?

B- For a < r < b, what is the value of the electric field strength?

C- What is the coefficient of 1/r in the correct expression for the electric field strength as a function of r for r > b?

D- What is the charge per unit length on the inner surface of the tube?

E- What is the charge per unit area on the inner surface of the tube?

F- What is the charge per unit length on the outer surface of the tube?

G- What is the charge per unit area on the outer surface of the tube?

A 14.5 m uniform ladder weighing 510 N rests against a frictionless wall. The ladder makes a 55.0° angle with the horizontal.

(a) Find the horizontal and vertical forces the ground exerts on the base of the ladder when an 810 N firefighter is 4.10 m from the bottom.
Magnitude of the horizontal force
N Direction

towards the wallaway from the wall    

Magnitude of the vertical force
N Direction

updown    

(b) If the ladder is just on the verge of slipping when the firefighter is 9.20 m up, what is the coefficient of static friction between ladder and ground?

A father racing his son has one-third the kinetic energy of the son, who has two-fifths the mass of the father. The father speeds up by 2.5 m/s and then has the same kinetic energy as the son. (a) What is the original speed of the father?(b) What is the original speed of the son?