physics please HELP !

74,851 results, page 92
  1. physics

    a small conducted sphere is attached to the end of an insulating rod .it carries a charge of +5.0*10-9 C. the plates ,which are 4.0 cm apart, are connected to a 50 000 V supply.
  2. physics

    A flywheel is making 180 r.p.m. and after 20 seconds it is running at 140 r.p.m. How many revolutions will it make, and what time will elapse before it stops, if the retardation is uniform ?
  3. Physics

    An advertisment claims that a certain 1200 kg car can accelerate from rest to a speed of 25 m/s in 8.0 s. what average power must the motor supply in order to cause this acceleration?
  4. physics

    a baseball is thrown at an angle of 24 degrees relative to the ground at a speed of 23.4m/s. the ball is caught 41.4798m from the thrower. how long is it in the air?
  5. physics

    How much force is the air exerting on the front surface of the book with dimensions 19 x 27 cm. Assume atmospheric pressure equal to 100,000 Pa.
  6. physics

    Two bodies of mass 3kg and 4kg are suspended at the ends of massless string passing over a frictionless pulley .the acceleration system is
  7. Physics

    Two concentric conducing spheres of radii 4 cm and 12 cm are given equal but opposite charges of 6 x 10^-8C. How much energy is stored in the system? How would I go about in beginning to solve this problem?
  8. Physics

    If a rocket is launched at an initial speed of 120m/s at an angle of 25 degrees, find the time of flight, range, and it's highest height.
  9. Physics

    A rocket moves upward, starting from rest with an acceleration of 35.0 m/s2 for 5.63 s. It runs out of fuel at the end of the 5.63 s but does not stop. How high does it rise above the ground?
  10. Physics

    a 45-kg box initially at rest is being pushed with a force of 950 N along a frictionless horizontal surface. What is the speed of the boz after traveling a distance of 2.0m
  11. Physics

    A rocket moves upward, starting from rest with an acceleration of 35.0 m/s2 for 5.63 s. It runs out of fuel at the end of the 5.63 s but does not stop. How high does it rise above the ground?
  12. Physics

    When maximum power is transferred to an external resistor R by a battery of emf E and internal resistance r, the ratio of r/R is? Answer 1:1 Can some please explain? Thankkks!
  13. Physics

    A rocket moves upward, starting from rest with an acceleration of 35.0 m/s2 for 5.63 s. It runs out of fuel at the end of the 5.63 s but does not stop. How high does it rise above the ground?
  14. physics

    An outfielder throws to the second baseman, a distance of 120ft at a 20degree angle. Whats the min velocity he has to throw the ball to get it to the base?
  15. Physics

    A rocket moves upward, starting from rest with an acceleration of 35.0 m/s2 for 5.63 s. It runs out of fuel at the end of the 5.63 s but does not stop. How high does it rise above the ground?
  16. physics

    Two equals negatives charges (-1.75x10^(-19) Coulb) are separated by an insulator at a distance of 0.230 mm. Find the electrostatic force between these electrons?
  17. Physics

    W.K.T, Magnetic Force qvB=mv^2/r ... n we know how to prove it too.... But how to show that the radius of curvature of the circular path is proportional to the linear momentum of the charge ?
  18. Physics

    A force of 250 N is just sufficient to start a 50 kg steel trunk moving across a wooden floor. Find the coefficient of static friction.
  19. Physics

    a plastic duck floats half-immersedi n water in the bathtub. What fraction of its volume would be immersed in a liquid of relative density 2.0?
  20. physics

    Two boxes of masses 3kg and 8kg respectively are moving with velocities 5m/s and 3m/s in opposite direction. If they stick together after impact, calculate their common velocity.
  21. physics

    A 2.2kg bowling ball with a velocity of 2m/s rolls along a level floor for 30m before coming to a halt. What is the coefficient of rolling friction?
  22. physics

    a proton moves in a circle in a uniform magnetic field of 1T, pointing into the page. Its speed is 1.5 x 10 ^5 m/s. What is the radius of its path? B q v = m v^2/r --------> r = m v/(B q) M=(1.67 * 10-27 ) V= (1.5 * 10^ 5) Q= (1T) B= (1.6 * 10-19 ) is
  23. Physics

    A ball is projected so as to reach a height h passes points p and q with velocites v/2 and v/3 where v is the initial velocity with which the body is thrown the distance between p and q in terms of h is
  24. Physics

    A rotating cylinder 7.95 kilometers in radius is designed to be used as a space colony. With what period must it rotate so the residents on it feel as heavy as they would on Earth?
  25. Physics

    By what amount will a 178 m long concrete slab on the Mackinac Bridge contract when going from +39C to -35C? The linear expansion coefficient is 10^-5 per C.
  26. physics

    electricity is measured in kilowatts-hours, kW*h. this quantity can be converted to which other unit that measures energy? a.Pascals b.Joules c.Newtons d. Watts
  27. physics

    A sphere is fired downwards into a medium with an initial speed of 40 . Part A If it experiences a deceleration of , where is in seconds, determine the distance traveled before it stops.
  28. Physics

    A stone popelled from a catalpult with the speed of 50m/s attained a height of 100m. Calculate the time of flight and angle of projection.
  29. modern physics

    Calculate the deBroglie wavelength of a^ 87Rb atom that has been laser cooled to 120 µK. (Assume that the kinetic energy is .3/2kBT)
  30. physics

    two perfect elastic balls of same mass m are moving with velocities u1 and u2 . they collide elastically n times. the kinetic energy of the system finally is?
  31. physics

    A rocket is projected horizontally with velocity 700meter per seconds from the top of a tower 100meter high. how long will it take to reach the ground?
  32. Physics

    A pulley system has an efficiency of 78.0 per- cent. The acceleration of gravity is 9.81 m/s2 . How much of the rope must be pulled in if a force of 469 N is needed to lift a 52 kg desk 2.78 m?
  33. Physics

    If it takes 5 seconds for the baseball to fall, how far from the tower will it land? I used vertical distance formula dy=1/2(g)t^2 and got 122.5 but its one of the answers in the multiple choice. Please help.
  34. Physics!

    Suppose that you are standing on a train accelerating at 0.39g. What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide?
  35. Chemistry/Physics

    When 1mol of a gas burns at constant pressure, it produces 2430J of heat and does 5kJ of work. Calculate change in H, q, and in kJ?
  36. Physics

    A Martian rover is moving up a hill sloped at 30.0° with the horizontal. If it has a constant velocity of 1.50 meters/second, calculate its vertical displacement after 21.0 seconds.
  37. physics

    how do we find the interpolation from a graph to determin the number of images which should be observer with a mirror angle of 90 degree and how do we calculate the line equation.
  38. physics

    A novice skier, starting from rest, slides down a frictionless 31.0° incline whose vertical height is 123 m. How fast is she going when she reaches the bottom?
  39. Physics

    A 200-Ù resistor, 40.0-mH inductor and a 2.00-ìF capacitor are connected in series with a 120-V rms source at 1000 Hz. What is the phase angle of this circuit?
  40. physics

    A bullet is fired straight up from a gun with a muzzle velocity of 208 m/s. Neglecting air resistance, what will be its displacement after 2.6 s? The acceleration of gravity is 9.8 m/s2 .
  41. physics

    An elevator and rider have a mass of 1600 kg combined. What is the tension force in the cable lifting them at a steady speed of 3 m/s? Assume no friction.
  42. physics

    A 2 kg metal plate slides down a 14-meter high slope. At the bottom its speed is 11.1 m/s. To the nearest Joule, what was the magnitude of the work done by friction?
  43. physics

    1.2g projectil e shot horiz. at a speed of 105m/s off a 124m high cliff. a) determine time taken by the projectile to return to the ground..
  44. Physics

    A bullet shot horizontally strikes the ground with a velocity of 150.0km/h (10 degrees below the horizontal), determine the height from which it was fired.
  45. Physics

    A 52kg ice hockey player moving at 11m/s slows down and stops over a displacement os 8.0m. Calculate the net force of the skater.
  46. Physics

    A 40 tonne jumbo jet accelerates down the runway at 5 m/s^2. What must be the thrust on each of its four engines? What is the horizontal force that a 700 N pilot exerts on his seat?
  47. Physics

    A dip needle is a small magnet mounted on a horizontal axis sot that it can swivel up or down. Where on eath will it point most nearly vertically and most nearly horizontally?
  48. physics

    A pendulum has a mass of 3-kg, a length of 1.3 meter, and swings through a (half) arc of 30 degrees. To the tenth of a Joule, what is its maximum Kinetic Energy?
  49. physics

    a 10 kg mass is attached to one end of a string with a lenght of 5m and whirled in a horizontal circle overheadd at a rate of 1 revolution per second what is tension in the sring

    Calculate a constant force required to bring an object of mass 2.0kg.moving with a velocity of 4.0m/s to rest in. 0.1sec and 2metre
  51. Physics

    A weightlifter raises a 90k-g barbell from the floor to a height of 2/2 m in 0.6 s. What was his average power output during his lift? Sorry I wrote it wrong the first time!
  52. Physics

    If the path-length difference between two identical and coherent beams is two wavelengths when they arrive on a screen, will they produce a dark or a bright spot?
  53. Physics

    A bicycle wheel is accelerating at the constant rate of 1.4 rev/s2 (a) If it starts from rest, what is the rotational velocity after 4.7s? (b) Through how many revolutions does it turn in this time?
  54. physics

    A 31.4-kg diver free falls from the diving board and hits the water with a speed of 10.0 m/s. Based on this information, the height of the tower is __________
  55. physics 2

    How many electrons must be removed from each of two 5.40kg copper spheres to make the electrical force of repulsion between them egual in magnitude to the gravatational attraction between them?
  56. PHYSICS ---HELP!

    A man doing push-ups pauses. His mass is 80-kg. Determine the normal force exerted by the floor on each hand and on each foot. a = 40 cm b = 95 cm c = 30 cm W = mg = 784 N
  57. physics

    a point mass of 12.5 kg is hung from an 18.3 m long rope and swings back and forth with an amplitude of 2.34m. what is the oscillation period for the pendulum system?
  58. physics

    If a loaded truck that can accelerate at 1 m/s2 loses its load and has four-fifths of its original mass, what acceleration can it attain if the same driving force acts on it?
  59. physics

    Driving home from school one day, you spot a ball rolling out into the street (see the figure ). You brake for 1.40 , slowing your 950- car from 16.0 to 9.50 .
  60. Physics

    A car travelling at 30m/s overcomes a frictional resistance of 100N while moving. Calculate the power developed by the engine.[1hp=0.75]
  61. physics

    a mass of 0.1kg falls freely under the action of gravity .find the force acting on it its momentum kinetic energy after 10s?
  62. physics

    A power line 10 meter high carries a current 200 amperes .Find the magnetic field of the wire at ground?
  63. physics

    Bob heads out into a lake at an angle of 34 with respect to the shore. If his boat is capable of a speed of 2.5 m/s, how far from land will he be in 7 min and 31 s ? Answer in units of m
  64. physics

    A ball of mass m is projected with a speed u at an angle theta with horizontol. Find the change in momentum after time t and when it reaches the ground
  65. physics, math, science

    a soccer ball is kicked on the ground at 8m/s. another player is standing 30 m away. if she needs to intercept it at 20m - how much time does she have and how fast must she run?

    In an archery practice an arrow was realesed from a bow with a velocity of 20m/s it strikes and slopes find at what rate the aarrow was aaccelarated
  67. physics

    A rocket moves upward, starting from rest with an acceleration of 26.3 m/s2 for 3.91 s. It runs out of fuel at the end of the 3.91 s but does not stop. How high does it rise above the ground?
  68. physics

    a worker pushing a wheelbarrow of mass 50 kg with a constant velocity along a horizontal surface whose coefficient of friction is 0.5 and the angle of force is 30 degree
  69. physics

    at what altitude should a satellite be placed into circular orbit so that its orbital period is 48 hours? the mass of the earth is 5.976x10^24 kg and the radius of the eatrh is 6.378x10^6 m.

    What is the angular momentum of a 2.7 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1600 rpm? How much torque is required to stop it in 4.4 s?
  71. physics

    Find the approximate gravitational red shift in 500 nm light emitted by a compact star whose mass is that of sun but whose radius is 10 km.
  72. physics

    Find the length of a simple pendulum that has a period of 5.00s . Assume g = 9.81 m/s2. Express your answer to three significant figures and include the appropriate units.
  73. Physics

    A 1.11 kg block slides down a 15.0 m long 32.0° incline at constant velocity. How much work is done by friction? (please help me show me how to solve using equation and where to plug the numbers)
  74. Physics

    A bolt is to be tightened with a torque of 8.0 N*m. If you have a wrench that is 0.35 m long, what is the least amount of force you must exert? the equation for this problem is t=Fr sinbeta, but the sin is not given What am I suppose to do?
  75. Physics

    STATE whether you expect the following entities to be in thermal equilibrium with their surroundings under normal circumstances. A. A desk - I think yes B. A person- I think yes C. The walls of a room- I think yes D. The sun- I think no
  76. Physics

    An Olympic long jumper is capable of jumping 8.44m. Assuming his horizontal speed is 5.644m/s as he leaves the ground, how high does he go?
  77. physics

    A car of mass 200g moving at 15.0m/s is accelerated to 25.0m/s in a time of 10.0 seconds determine the accelerating force and calculate the work done on the body

    How does the magnitude of the electrical force between two charged objects depend on the distance between the charges? I really frustrated right now, and I can't figure out the answer too this question. Help pleeease :)
  79. Physics

    Suppose you wish to make a solenoid whose self-inductance is 1.2 mH. The inductor is to have a cross-sectional area of 1.2 10-3 m2 and a length of 0.048 m. How many turns of wire are needed?
  80. physics

    the 3 lb block A rests on a surface for which the coefficient of kinetic is Mk=.30 determine the distance the 8-lb cylinder B must descend so that A has a speed of Va = 5ft/s starting from rest.
  81. physics

    Three blocks on a frictionless surface are connected by massless strings, with M1 = 1.40 kg, M2 = 2.40 kg, and M3 = 3.60 kg. Due to the force F acting on M3, as shown, the system accelerates to the right. Given that T1 is 3.50 N, calculate T2
  82. Physics

    what is the moment of interia of a solid cylinder of radius R=0.0950m thickness t=0.015m total mass M=3.565kg? show your work
  83. Physics

    a hoop of radius .5 m & mass .2 kg is released from rest & rolls down an inclined plane. how fast is it moving when it has dropped a vertical distance of 3 m?
  84. physics

    an thelet completes one round of circular track of diameter 200m in 40 secomds. wht will be the distance covered t the end of 2min & 20 s.
  85. Physics - studying for finals

    (a) Write the expression for y as a function of x and t in SI units for a sinusoidal wave traveling along a rope in the negative x direction with the following characteristics: A = 5.00 cm, λ = 75.0 cm, f = 5.00 Hz, and y(0, t) = 0 at t = 0. (Use the
  86. Physics

    Rotating initially at 1800 rpm, a wheel with a diameter of 74.0 cm is brought to rest in 11.0 s. Calculate the magnitude of its angular acceleration in radians/second^2
  87. Physics

    A 120-V rms voltage at 1000 Hz is applied to a resistor and an inductor in series. If the impedance of this circuit is 110 Ù, what is the maximum value of the current?
  88. Physics

    Your electric jug element produces 1.5kW of power. What is the minimum time it will take to heat 1.5L of water from 20 degrees Celcius to boiling
  89. Physics

    You throw a baseball straight up at 40 m/s and it reaches its peak after 4.00 seconds. What is its speed when it falls back into your hand? What is its displacement? What distance has it traveled?
  90. physics

    a kangaroo jumps to a vertical height of 2.55m.How long was it in the air before returning to Earth? pleaseee anwser it is due in 1 day!!!!
  91. Physics

    You drive your car 2 km to the gas station, 4 km to the shopping mall to let your mother off, and 4.5 km back home. The trip takes 20 min. What is your velocity in m/s?
  92. Physics

    A 17 kg child descends a slide 3.5 m high and reaches the bottom with a speed of 1.5 m/s. How much thermal energy due to friction was generated in this process?
  93. physics

    Geosynchronous communications satellites are placed in a circular orbit that is 3.59 107 m above the surface of the earth. What is the magnitude of the acceleration due to gravity at this distance?
  94. Physics HELP

    Two blocks of masses m1 = 6 kg and m2 = 6 kg are on either side of the wedge shown in the figure above. Find their acceleration and the tension in the rope. Ignore friction and the pulley.
  95. Physics

    What is the threshold frequency for the photoelectric effect on lithium (phi= 2.93eV)? What is the stopping potential if the wavelength of the incident light is 400nm?
  96. physics

    if you wished to warm 100 kg of water by 15 degrees celsius for your bath, how much heat would be required? (give your answer in calories and joules)
  97. Physics

    William Tell fired an arrow with a velocity of 100 m/s at an angle of 30˚. How long will it take to reach its highest point? Please show work
  98. Physics

    A uniform beam of mass 2kg and length 4cm is rotated about an axis 8cm from one end.Determine it's moment of inertia
  99. physics

    a body is dropped from the roof of a builindgs 10 m high .calculate the time of fall and the speed with which it hits the ground .take g=10m/second sqare
  100. Physics

    Item 10 Two equally charged, 1.00 spheres are placed with 2.00 between their centers. When released, each begins to accelerate at 225 m/s2 Part A - What is the magnitude of the charge on each sphere? =