A skier starts from rest at the top of a hill that is inclined at 10.8° with respect to the horizontal. The hillside is 245 m long, and the coefficient of friction between snow and skis is 0.0750. At the bottom of the hill, the snow is level and the coefficient of friction is unchanged. How far does the skier glide along the horizontal portion of the snow before coming to rest?

10-Two events occur at the same place in a frame S and are separated by a time interval of 1s. The same events are separated by a time interval of 4 s in frame S'. What is the spatial separation of the events in frame S'?

Calculate the electric field(magnitude and direction) at the center of a square 52.5 cm on a side if one corner is occupied by a - 38.8 μC charge and the other three are occupied by - 27.6 μC charges.

answer is not 7.3*10^6 or 7.3*10^-7

True or False, please answer only if you are sure:

A) The work done by a constant force acting on an object is independent of the orientation of the force relative to the motion of the object
B) The work done to raise a box onto a platform depends on how fast it is raised. (Neglect friction, assume it starts on the ground at rest, and ends up resting on the platform)
C) The kinetic energy of a moving object is always positive.
D) The kinetic energy of an object is independent of the direction of the motion involved.
E) Work cannot be done in the absence of motion.
F) The work-energy principle is perfectly valid even when there are frictional forces acting

Two objects, O1 and O2, have charges +3.0μC and −5.0μC, respectively, and a third object, O3, is electrically neutral.

Part A:

What is the electric flux through the surface A1 that encloses all three objects?

Part B:

What is the electric flux through the surface A2 that encloses the third object only?

"The CMB represents the heat left over from the Big Bang. It is the oldest electromagnetic radiation in the universe."

Why "heat"? Isn't very cold?

What is the connection between the blackbody and the CMB.

I would like to have a simple explanation for the CMB, with your own words. Please. :-)

Thanks

A test charge of +3.00 μC is placed halfway between a charge of +8.00 μC and another of +5.00 μC separated by 10.00 cm. (a) What is the magnitude of the force on the test charge? (b) What is the direction of this force (away from or toward the +8.00 μC charge)?

A plane with a speed of 800.0 km/hr due east passes directly above a train traveling due southeast at 100.0 km/hr on a straight level road. The altitude of the aircraft is 10.0 km. How fast is the distance between the plane and the train increasing 45 s after the aircraft passes directly above the train?

The loaded cab of an elevator has a mass of 3.6 × 10³ kg and moves 216 m up the shaft in 17 s at constant speed. At what average rate does the force from the cable do work on the cab?

What range of velocities might an electron have if it is confined to a 0.4-nm-wide region? And if it is confined to about the size of an atom (0.1-nm-wide region)? Compare this to your previous knowledge about the speed of electrons in the atom. What does this mean?

A 10 cm long thin glass rod uniformly charged to +10 nC and a 10 cm long thin plastic rod uniformly charged to -10nC are placed side by side 4 cm apart.

a. Find the electric field at distances 1.0 cm, 2.0 cm and 3.0 cm from the glass rod along the line connecting the midpoints of the two rods. (Hint: treat the rods as a uniform line of charges.)

b. If the plastic rod is exchanged for a glass rod of the same size uniformly charged to +10 nC, what is the new electric field at 1.0 cm, 2.0 cm and 3.0 cm?

Blue light of wavelength 470 nm passes through an interference grating with a slit spacing of0.001 mm and makes an interference pattern on the wall.

How many bright fringes will be seen?

A solid cylinder with a mass of 3 kg, a radius of 25 cm, and a length of 40 cm is rolling across a horizontal floor with a linear speed of 12 m/s. The cylinder then comes to a ramp, and, as it is rolling up this ramp without slipping, it is slowing down. When the cylinder finally comes to a stop and begins rolling back down the ramp, how high is it above the floor?

1. How can contrast be achieved in a display using texture? Color? Line? Give an example of each

2. Describe the concept of proportion, and explain why it is important to any visual presentation

A meteor with a mass of 1 kg moving at 20 km/s collides with Jupiter's atmosphere. The meteor penetrates 100 km into the atmosphere and disintegrates. What is the average force on the meteor once it enters Jupiter's atmosphere (Ignore gravity).

*The answer is 2 x 10^3 N but I have no idea why.