Recent content by Kalie

  1. K

    Ball thrown upward and another is dropped

    Draw a picture, with the applied forces.
  2. K

    Force and Motion (net force)

    The 'net force' in the statements below is the sum of ALL forces acting on the body. During the collision of a car with a locomotive, the locomotive exerts an equal size force on the car as the car exerts on the locomotive. False If an object's speed does not change, no net force is...
  3. K

    Electric field (easy at least I thought so)

    The electric field strength 5.0 cm from a very long charged wire is 2000 N/C. What is the electric field strength 10.0 cm from the wire? Okay I thought that since the radius is double what it was before using the equation: E= K*q*(r head)/(r^2) I said that it decreases 1/4 and becomes...
  4. K

    Carnot Refrigerator coefficient of performance

    A Carnot refrigerator operating between -10.0 C and 40.0 C extracts heat from the cold reservoir at the rate 300 J/s. What are (a) the coefficient of performance of this refrigerator, (b) the rate at which work is done on the refrigerator and (c) the rate at which heat is exhausted to the hot...
  5. K

    Heat needed to change temperature of hydrogen gas

    nevermind monatomic at that temp
  6. K

    Heat needed to change temperature of hydrogen gas

    Oh! But When I do that I get .65/2 = .325 .325*20.775*50 = 337.6 which is still wrong
  7. K

    An Air Conditioner: Refrigerator or Heat Pump?

    Air conditioners operate on the same principle as refrigerators. Consider an air conditioner that has 7.00 kg of refrigerant flowing through its circuit each cycle. The refrigerant enters the evaporator coils in phase equilibrium, with 54.0% of its mass as liquid and the rest as vapor. It flows...
  8. K

    Heat needed to change temperature of hydrogen gas

    But i also calculated it for monotomic too....
  9. K

    Heat needed to change temperature of hydrogen gas

    A rigid container holds 0.650 of hydrogen gas. How much heat is needed to change the temperature of the gas from 50 K to 100 K? All right I know this is easy but for some reason I can't get the right answer what i have been doing is using the equation Q=nC_v(T_f-T_i) Hydrogen gas is 1 g/mol...
  10. K

    Roling vs Sliding Down an incline

    Think about 2 objects (one rolling one sliding) down an incline. In terms of energy, see what you came up with and how they differ...be verbose! All right I know that the rolling object would go down the incline faster and...i'm not sure but I think...the sliding one would gather the most...
  11. K

    Oscillations of air-track glider

    A 160 g air-track glider is attached to a spring with spring constant 4.40 N/m. The damping constant due to air resistance is 2.40×10−2 kg/s. The glider is pulled out 23.0 cm from equilibrium and released. How many oscillations will it make during the time in which the amplitude decays to...
  12. K

    Pressure pn a Dam

    As the reservoir behind a dam is filled with water, the pressure that the water exerts on the dam increases. Eventually, the force on the dam becomes substantial, and it could cause the dam to collapse. There are two significant issues to be considered: First, the base of the dam should be able...
  13. K

    Torque? Rotation it has the Word Pivot

    Torque? Rotation it has the Word Pivot.... A forearm can be modeled as a 2.50 kg, 32-cm-long "beam" that pivots at the elbow and is supported by the biceps. http://session.masteringphysics.com/problemAsset/1001007/10/knight_Figure_13_58.jpg How much force must the biceps exert to hold a 430...
  14. K

    Static Equilibrium of the Arm

    You are able to hold out your arm in an outstretched horizontal position because of the action of the deltoid muscle. Assume the humerus bone has a mass m=3.6, length L=0.66 and its center of mass is a distance L1=0.33 from the scapula. (For this problem ignore the rest of the arm.) The deltoid...
  15. K

    Newton's Theory of Gravity and impact speed

    A 1.0 kg object is released from rest 500 km above the earth. A. What is its impact speed as it hits the ground? Ignore air resistance B. What would the impact speed be if the earth were flat? I don't know how to start this. I said that v=sqrt(2G*M_e*m/(R_e+300))= 1.33*10^9 but that is...
Top