• How many possible directions are there for the frictional force?

• Physicists categorize the frictional force according to the relative motion between the two surfaces. What are some of the categories?

• One category of frictional forces is the static frictional force. What is the relative motion between the surfaces for this category? Describe a theory of static frictional forces.

• Another category of frictional forces is the kinetic frictional force. What is the relative motion between the surfaces for this category? Describe a theory of kinetic frictional forces.

In an experiment, 426 g of water is in a copper calorimeter cup of mass 205 g. The cup and the water are at an initial temperature of 10.9 oC. An unknown material with a mass of 361 g at a temperature of 296.1 oC is placed in the water. The system reaches thermal equilibrium at 36.1 oC. What is the specific heat of the unknown material? units = J/kg-C

Discuss the general design of light and heavy water reactors

Three children are riding on the edge of a merry-go-round that is 122 kg, has a 1.60 m radius, and is spinning at 17.3 rpm. The children have masses of 19.9, 29.5, and 40.8 kg. If the child who has a mass of 29.5 kg moves to the center of the merry-go-round, what is the new angular velocity in rpm?

A 425 kg satellite is in a circular orbit at an altitude of 400 km above the Earth's surface. Because of air friction, the satellite eventually falls to the Earth's surface, where it hits the ground with a speed of 2.00 km/s. How much energy was transformed to internal energy by means of friction?
J

1-What is the expression for the thin lens equation? Define all the terms in the expression.

2-Describe the three properties that determine the focal length of a lens.

3-Define the following:
i. Converging lens______

ii. Diverging lens_______

iii. Focal length___________

iv. Focalpoint____________

v. Object distance_______

vi. Imagedistance___

vii. Real image___

viii. Virtual image

What is the magnitude of the tangential acceleration of a bug on the rim of a 12.5-in.-diameter disk if the disk accelerates uniformly from rest to an angular speed of 75.0 rev/min in 3.50 s?
m/s²

(b) When the disk is at its final speed, what is the magnitude of the tangential velocity of the bug?
m/s

(c) One second after the bug starts from rest, what is the magnitude of its tangential acceleration?
m/s²

(d) One second after the bug starts from rest, what is the magnitude of its centripetal acceleration?
m/s²

(e) One second after the bug starts from rest, what is its total acceleration? (Take the positive direction to be in the direction of motion.)

1. Explain the difference between an elastic and inelastic collision.

2. How many times more energy is required to increase the speed of a 2200 pound car by 10 mph if car initially is going 30 mph versus it initially going 80 mph? (convert to metric)

3. how many horse power are required to accelerate from 80 mph to 90 mph in 0.75 seconds? (tell me the average horsepower. 1 horsepower = 750 watts)

4. will a solid lead cylinder float or sink in mercury? why? (Pp= 11.34 g/cm^3, Hg= 13.53 g/cm^3)

5. how many centimeters of the lead cylinder would be submerged in the mercury if its dimensions are (radius = 5cm, height = 10cm)

Identify and briefly describe the five key components of the “scientific method”

uranium-235 is used in a nuclear power plant as fuel source because

1)Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 39.7 km/s and 53.7 km/s. The slower planet's orbital period is 8.02 years. (a) What is the mass of the star? (b) What is the orbital period of the faster planet, in years?

2)Two satellites are in circular orbits around the earth. The orbit for satellite A is at a height of 461 km above the earth’s surface, while that for satellite B is at a height of 881 km. Find the orbital speed for (a) satellite A and (b) satellite B.

3)The drawing shows a baggage carousel at an airport. Your suitcase has not slid all the way down the slope and is going around at a constant speed on a circle ((r = 14.0 m) as the carousel turns. The coefficient of static friction between the suitcase and the carousel is 0.570, and the angle θ in the drawing is 18.7°. How much time is required for your suitcase to go around once? Assume that the static friction between the suitcase and the carousel is at its maximum.

4) A satellite is in a circular orbit about the earth (M_E = 5.98 x 10²⁴ kg). The period of the satellite is 2.37 x 10⁴ s. What is the speed at which the satellite travels?

why does a satellite in a circular orbit travel at a constant speed (choose all that apply)

a. there is no force acting along the direction of motion of the satellite
b. the only force is the force of gravity
c. there is no component of net force in the radial direction
d. the net force acting on the satellite is toward the center of the path
e. There is a component of the net force acting in the direction of the motion of the satellite
f. the gravitational force acting on the satellite is balanced by the centrifugal force

(I know its not F bc centrifugal force its really a real thing but the rest... idk)

a box of mass 10 kg is pressed but not attached to an ideal spring compressing the spring a distance of 2.5cm after it is released the box slides up a frictionless incline and eventually stops at a vertical height h, the same experiment is repeated with the same box and spring but with an initial compression of 5cm the vertical height the box reaches the second time is ______

i'm thinking its 2x because its 2x the compression but let me know I might be very very wrong

A manufacturer produces either edible honeycomb or honey from the raw honeycomb harvested from the beehives. To produce edible honeycomb, raw honeycomb is fed to a cutter that produces 30 edible combs per raw comb, and the manufacturer wants to produce 1200 edible combs an hour. The raw honeycomb that is to be made into honey is put through an uncapping and filter machine that separates both the wax and the honey from the frame. The honey is then split, part going to storage and part going to a heater which warms the honey before packaging.

If each raw honeycomb has a 1 pound frame, holds 7 pounds of honey, and has an average weight of 10 pounds, how much wax is produced (lbs/hr) when 300 raw honeycombs/hour is fed to the system?
How much extra honey (lbs/hr) must be stored to keep production at 1500 lbs/hr for the warm honey?
If honey enters the heater at 25°C and leaves at 55°C, how much energy does the heater use (kW)?

Given information: Cp of honey:
1.9 + 28.8×10^-4 T + 6.4×10^-5 T^2 + 6.9×10^-8 T^3

Units of specific heat are Celsius.

A block having a mass of 10.0 kg is pressed against the wall by a hand exerting a force F inclined at an angle θ of 52° to the wall as shown below. The coefficient of static friction µstat between the block and the wall is 0.20. We shall investigate the question of how large the force F must be to keep the block from sliding along the wall. There is more physics here than initially meets the eye. Think about the situation in terms of your everyday experience (or better yet, actually try it out): If you start out with a small value of F, the block will tend to slide downward; as you increase F, you reach the point at which the block will no longer slide; as you continue increasing F, the block stays put until, at some larger value of F, it might even begin to slide upward. This is the physics to be investigated, both algebraically and numerically.

(a) First draw well-separated force diagrams of the block and the region of the wall where the two are in contact (1) for the case in which F is small enough that the block tends to slide downward and (2) for the case in which the block tends to slide upward. Denote the various forces by appropriate algebraic symbols; do not put in numbers at this point. Describe each force in words and identify the third law pairs.

(b) Applying Newton’s second law, obtain algebraic expressions for F in terms of m, g, µstat, and θ for case 1, in which the block is just about to start sliding downward and for case 2, in which it is just about to start sliding upward.

(c) Now put in the various numbers and calculate the value of F for each of the two cases. How large is the spread between the two values? Does your result make physical sense? What is going on at the wall when F lies between the two extremes you have calculated? What happens to the frictional force when F lies between these two extremes?

(d) Return to the algebraic expression for case 2 in which the block is just about to slide upward. What does this expression say happens to F if you keep m and θ constant but increase the value of µstat? What is the equation telling us happens at the point at which µ is large enough to make the denominator of the expression equal to zero? Is it possible to make the block slide upward with a sufficiently large F at a fixed value of θ regardless of the value of µstat? Solve for the value of µstat at which it becomes impossible to make the block slide upward, showing that this value depends only on θ and is independent of the weight of the block. Do you find this result strange? Why or why not? Could you have anticipated it without having made the mathematical analysis?