Search results

  1. P

    Probability and Statistics, very basic stuff

    Homework Statement Suppose that a dietitian has 3 groups of foods, having 5 items in the first group, 7 items in the second group and 2 items in the third group. 1. How many meals are possible containing one food from each food group? 2. How many meals are possible containing 3 foods from...
  2. P

    Spring and Oscillation

    A 5.00 g bullet moving with an initial speed of v0 = 405 m/s is fired into and passes through a 1.00 kg block, as in Figure P13.58. The block, initially at rest on a frictionless horizontal surface, is connected to a spring with a spring constant of 950 N/m. Figure P13.58 (a) If the block...
  3. P

    Among Simple harmonic oscillation, simple pendulum and physical pendulum

    What is the similarity between Simple Harmonic Oscillation(SHO), simple pendulum and a physical pendulum? I never understood it. Like whats the physical significance of SHO, or the energy and momentum change in oscillating motion?
  4. P

    Thermal Concrete Physics

    Homework Statement Two concrete spans of a L = 270 m long bridge are placed end to end so that no room is allowed for expansion (Fig. P10.55a). If the temperature increases by T = 21.0°C, what is the height y to which the spans rise when they buckle (Fig. P10.55b) Homework...
  5. P

    Gases and Pressure

    Homework Statement An expandable cylinder has its top connected to a spring with force constant 2.00 103 N/m. (See Fig. P10.58.) The cylinder is filled with 4.00 L of gas with the spring relaxed at a pressure of 1.00 atm and a temperature of 20.0°C. (a) If the lid has a...
  6. P

    Fluid Flow

    Homework Statement Figure P9.81 shows a water tank with a valve at the bottom. If this valve is opened, what is the maximum height attained by the water stream coming out of the right side of the tank? Assume that h = 8.0 m, L = 1.50 m, and = 30° and that the cross-sectional area at A is very...
  7. P

    Rotational Kinetic Energy and Work

    The puck in Figure P8.51 has a mass of 0.120 kg. Its original distance from the center of rotation is 40.0 cm, and it moves with a speed of 85.0 cm/s. The string is pulled downward 15.0 cm through the hole in the frictionless table. Determine the work done on the puck. (Hint: Consider the change...
  8. P

    Astronaut and weightlessness

    Why does an astronaut in a space craft orbiting the Earth experience a feeling of weightlessness?
  9. P

    Torque and Force example

    (a) Give an example in which the net force acting on an object is zero and yet the net torque is nonzero. (b) Give an example in which the net torque acting on an object is zero and yet the net force is nonzero. can b be torque= Tension(12 N)(radius 0m) ?
  10. P

    Figure Skating and Angular Momentum

    In Figure Skating, when the players are rotating, there’s a way to slow him/herself down, do you know what’s that? Using the knowledge of angular momentum, analyze qualitatively why he/she can achieve such effect?
  11. P

    Friction or some force acting on momentum of an object

    Would forces like friction and air resistance increase momentum or decrease it? I would think if a force acts on momentum it would decrease the momentum of an object. Is that right? P= mv P= Ft
  12. P

    Work force question

    In most circumstances, the normal force acting on an object and the force of static friction do no work on the object. However, the reason that the work is zero is different for the two cases. In each case, explain why the work done by the force is zero.
  13. P

    Bowling Ball problem

    A bowling ball is suspended from the ceiling of a lecture hall by a strong cord. The ball is drawn away from its equilibrium position and released from rest at the tip of the demonstrator's nose, as shown in Figure Q5.8. If the demonstrator remains stationary, explain why the ball does...
  14. P

    Momentum and Energy- Major help needed

    A small block of mass m1 = 0.300 kg is released from rest at the top of a curved wedge of mass m2 = 2.00 kg, which sits on a frictionless horizontal surface as in Figure P6.59a. When the block leaves the wedge, its velocity is measured to be 4.00 m/s to the right, as in Figure P6.59b...
  15. P

    Can the kinetic energy of a system be negative?

    Can the kinetic energy of a system be negative? Explain why or why not? Also I know gravitational potential energy of a system can be negative but I need a better explanation on why it is so.
  16. P

    Energy Question- Major help needed

    Problem A skier starts from rest at the top of a frictionless incline of height 20.0 m, as in Figure 5.19. As the bottom of the incline, the skier encounters a horizontal surface where the coefficient of kinetic friction between skis and snow is 0.225. Find the horizontal distance the skier...
  17. P

    Strings and Pulleys - Find the energy

    Three objects with masses m1 = 7.0 kg, m2 = 10.0 kg, and m3 = 14.0 kg, respectively, are attached by strings over frictionless pulleys, as indicated in Figure P5.32. The horizontal surface is frictionless and the system is released from rest. Using energy concepts, find the speed of m3 after it...
  18. P

    Work and Forces HELP

    If a man lifts a 15.0 kg bucket from a well and does 3.00 kJ of work, how deep is the well? Assume that the speed of the bucket remains constant as it is lifted.
  19. P

    Force- Major Help needed

    Suppose that in the same Atwood setup another string is attached to the bottom of m1 and a constant force f is applied, retarding the upward motion of m1. If m1 = 4.00 kg and m2 = 8.00 kg, what value of f will reduce the acceleration of the system by 50%? Now I got the equations for these two...
  20. P

    Force Problem help

    Three objects are connected by light strings as shown in Figure P4.62. The string connecting the m1 = 4.00 kg mass and the m2 = 4.00 kg mass passes over a light frictionless pulley. Figure P4.62 (a) Determine the acceleration of each mass. m/s2 (magnitude) (b) Determine the...
  21. P

    Determining distance(m)

    The determined Wile E. Coyote is out once more to try to capture the elusive roadrunner. The coyote wears a new pair of Acme power roller skates, which provide a constant horizontal acceleration of 15 m/s2, as shown in Figure P3.73. The coyote starts off at rest 70 m from the edge of a cliff at...
  22. P

    Determining angle and ratio in 2d motion

    When baseball outfielders throw the ball, they usually allow it to take one bounce on the theory that the ball arrives sooner this way. Suppose that after the bounce the ball rebounds at the same angle as it had when released (Fig. P3.70) but loses half its speed. (a) Assuming the ball is...
  23. P

    2 dimensional Motion

    A Chinook Salmon has a maximum underwater speed of 3.58 m/s, but it can jump out of water with a speed of 6.56 m/s. to move upstream past a waterfall, the salmon does not need to jump to the top of the fall, but only to a point in the fall where the water speed is less than 3.58 m/s; it can then...
  24. P

    Vector question HELP

    An airplane flies 200 km due west from city A to city B and then 305 km in the direction of 34.0° north of west from city B to city C. (a) In straight-line distance, how far is city C from city A? (b) Relative to city A, in what direction is city C? for a cant u do a^2 + b^2= c^2...
  25. P

    Measuring height

    help with part b It has been claimed that an insect called the froghopper (Philaenus spumarius) is the best jumper in the animal kingdom. This insect can accelerate at 4400 m/s2 over a distance of 2.0 mm as it straightens its specially designed "jumping legs." I got this right (a)...
  26. P

    Basic Time and Distance Measurement Help

    Vroom-vroom! As soon as a traffic light turns green, a car speeds up from rest to 50.0 mi/h with a constant acceleration of 8.60 mi/hs. In the adjoining bike lane, a cyclist speeds up from rest to 20.0 mi/h with a constant acceleration of 14.5 mi/hs. Each vehicle maintains a constant velocity...
  27. P

    Acid/Base Question

    Answer the following questions t or f a) Combining 0.3 moles of any acid with 0.3 moles of any base in water will always result in a pH value of 7.0 b) A 1 M solution of HCl and a 1 M solution of HNO3 have identical pOH values c) Combining equal volumes of a...
  28. P

    Reducing Agents

    Which of the following are reducing agents ? a) H2 b) Cl2 c) I2 d) MnO4- e) C I would think abcd would be good reducing agents, but that isnt right.
  29. P

    4Cu + O2 --> What is the name of the compound ?

    1. [1pt] The below reaction gives one ionic compound as a product. 4Cu + O2 --> What is the name of the compound ? An example of the correct answer format would be lead(II) nitrate note the space Its going to be copper(I) oxide right, but I dont understand why? Also...
  30. P

    Help with Chemistry problem

    Iridium has a face-centered cubic unit cell. The density of iridium is 22.61 grams per centimeter cubed. What is the diameter, in angstroms, of the iridium atom ? Atomic weight of Iridium = 192.1