physics please HELP !

74,851 results, page 83
  1. physics science

    Please can you help as I am stuck, Describe ib detail, how you would carry out an investigation to measure the density of a block of aluminium? Thankyou
  2. physics

    an airplane has a takeoff speed of 80 meters per second which it reaches 35 seconds after starting from rest. What is the minimum length of the runway?
  3. Physics

    Find the length of an inclined plane that will reach a platform 8ft high and form 16degree with the ground
  4. Grade 11 Physics - Light Unit

    Why must rays be shone in the centre of a flat surface? Describe the difficulty that's results if this is not done.
  5. physics

    a rock with a mass of 2 kg is thrown from the top of a cliff 75 m high with a velocity of 10m/s. how much Kinetic energy does it have when it gets to the bottom?
  6. physics science

    Please can you help as I am stuck, Describe ib detail, how you would carry out an investigation to measure the density of a block of aluminium? Thankyou
  7. Physics

    a 4.0 cm high object is placed 5.10 cm from a concave mirror whose redius of curvature is 21.2 cm. Find the inmage distance and the image size.
  8. Physics

    How much heat, expressed in Kwh, is required to raise the temperature of water in a 20,000 gallon pool by 10 degrees C. ?
  9. physics

    Find the limiting velocity of a rain drop assuming diameter of 5.0×10^-4m.The density of air relative to water is 1.3×10^-3
  10. Life orentation,maths,physics,business,geography

    Explain three ways in wich you can help to adress poverty and aids in s.a
  11. physics

    a fan rotates speed of 600rev per min the power is cut it stopped after 60 rev find time
  12. physics

    The car is travelling along the road with a speed of v  (300 / s) m/s, where s is in meters. Determine the magnitude of its acceleration when t = 3 s if t = 0 at s = 0. ( ans: a = 1.28 m/s2).
  13. physics

    Two freight cars, each with a mass of 2.5 multiplied by 10^5 kg, collide and stick together. One was initially moving at 3.4 m/s and the other was at rest. What is their final speed?
  14. Physics

    A car starts from rest and accelerates uniformly at 2m/s2 for 10 sec . Find the velocity and displacement at the end of 10 seconds .
  15. Physics

    Two ants race across a table 58cm long. One travels at 4.8 cm/s and the other at 3 cm/s. When the first one crosses the finish line, how far behind is the second one? Answer in units of cm
  16. Physics

    Show that 480 W of power is expended by a weightlifter when lifting a 60-kg barbell a vertical distance of 1.2 m in a time interval of 1.5 s.
  17. Physics

    What is the gravitational field strength at a place 220km above Earth's surface, the altitude of many piloted space flights?
  18. physics

    What is the acceleration (in meters/second^2) of a freely falling 74.0 kg sky-diver, if air resistance exerts a force of 264 N?
  19. Physics

    Calculate the torque on a coil in a motor of length 0.2m and a width of 0.1m which carries a current of 5A placed in a magnetic field of 0.5T and has 1 turn.
  20. Physics

    Suppose a cube that measures 0.020 m on each side were made of water. Find its volume, mass, and weight.
  21. physics

    A particle (p) moves along the curved surface (s). Show that p will remain in contact with s provided that at all times its speed v≥√rgcosteta.
  22. physics

    You are driving north on a highway. Then, without changing speed, you round a curve and drive east. Does your velocity change?
  23. Physics

    How much work is done by a boy weighing 450. Newtons while carrying a 20.0 kilogram package up a 2.00 meter flight of stairs?
  24. physics

    A pendulum has a mass of 3-kg, a length of 2 meters and swings through a (half)arc of 27.3 degrees. What is its Amplitude to the nearest centimeter ?
  25. Physics

    What types of material would be a good choice to shield a sensitive electronic device from stray electric fields?
  26. physics

    If a flea can jump straight up to a height of 0.310 m, what is its initial speed as it leaves the ground? How long is it in the air?
  27. Physics

    If a space station must "provide one sixth the magnitude of the acceleration due to gravity on Earth" Can I use 9.81ms^-2/6 or is that too simple? Thanks.
  28. physics

    A barometer is taken from the base to the top of a 554 m tower. Assuming the density of air is 1.29 kg/m3, what is the measured change in pressure?
  29. physics

    A uniform steel chain 20 m long and with a mass of 5 kg per m, hangs vertically. Compute the work required to wind it up
  30. Physics

    Computer the power output in watt of a machine that lift a 50kg crete through a height of 20cm in 1minute
  31. Physics

    Calculate the net charge on a substance con- sisting of a combination of 1.9 × 10^13 protons and 3.9 × 10^13 electrons. Answer in units of C.
  32. physics

    calculate the horizontal force that must be applied to produce an acceleration of 72 m/s^2 for a 0.034 kg punk on a friction less air table
  33. Physics

    A pendulum has a mass of 3.2 kg, a length of 2 meters and swings through a (half)arc of 28.1 degrees. What is its amplitude to the nearest centimeter?
  34. physics

    Calculate how many joules of energy would be needed to take 2kg of ice at -5 and turn it all to steam at 100 degees celcius?
  35. Physics

    Where must an object be placed to have a magnification of 3.74 in front of a converging lens of focal length 14.1 cm? Answer in units of cm
  36. physics 11

    a small 900kg sports car can deliver 100Hp to the pavement. how quickly can it reach 30m/s from rest?
  37. physics

    How do the pressure variations with depth affect our ability to explore the ocean? Consider the challenges of scuba diving and submarines.
  38. physics

    A 4.2 kg mass undergoes an acceleration given by ~a = ax ˆı + ay ˆ , where ax = 0.6 m/s 2 and ay = 4.8 m/s 2 . Find the magnitude of the resultant force. Answer in units of N
  39. Physics

    The displacement from the equilibrium caused by a wave on a string is given by: y(x,t) = (-0.00200 m)sin[(40m^-1)x-(800s^-1)t]. What is the number of waves in 1 m?
  40. Physics

    If a person jumped off the side of a ship from 20 feet high what speed would they be travelling at when they impact the water? Thanks Mike
  41. Physics

    In grandpa’s time automobiles were previously manufactured to be as rigid as possible, whereas autos are now designed to crumple upon impact. Why? Please help; Thank you in advance for the help...
  42. physics

    Charge polarization is normally produced by ____________________. A) nuclear interactions.B) contact.C) induction.D) friction.E) electrostatic means.
  43. physics

    An object is dropped from a platform 400 ft high. Ignoring wind resistance, how long will it take to reach the ground?
  44. Physics

    If Galileo and his assistant were 16 km apart, how long would it take light to make the round-trip? How does this time compare with reaction times of about 0.4 s?
  45. Physics

    What is gravitational force of a 65kg person that is on the surface of the moon has a mass of 7.348 x 10^22kg and radius of 1731km?
  46. physics

    Five forces act on an object. (1) 57 N at 90° (2) 40 N at 0° (3) 77 N at 270° (4) 40 N at 180° (5) 50 N at 60° What are the magnitude and direction of a sixth force that would produce equilibrium?
  47. AP physics

    suppose that the surface (radius=r) of the space station is rotating at 35.8 m/s. what must be the value of r for the astronauts to weigh one-half their earth weight?
  48. Physics

    A baseball was hit at 45m/s at an angle of 45 degrees above the horizontal. How long did it remain in the air? How far did it travel horizontally?
  49. physics

    a toy moves on a horizontal surface with a speed of 3m/ makes 8 turns in 5 seconds,whats the diameter of the wheel?
  50. physics

    three resistors of 2ohm, 3ohm and 4 ohm are connected in (a) series (b) parallel. find the equivalent resistance in each case
  51. physics

    a man holds a child on his shoulders while watching a football match. How much work has he done if the game lasts for 2 hours
  52. physics

    A female gymnast weighs 200 N. If she is hanging stationary from a high bar,how many forces are acting on her? A. one B.five C.four D.two E.three WOuld it be choice A or D?
  53. physics

    A ball is thrown directly downward with an initial speed of 8.95 m/s, from a height of 29.0 m. After what time interval does it strike the ground?
  54. Physics

    The materials with the lowest resistance are called a) conductors b)superconductors c)semiconductors d) insulators I can't decide between a) or b) but if I had to choose one would the correct one be b)?
  55. physics

    Solid and hollow cylinders both roll from rest down an inclined plane. Explain the difference in speeds at the bottom.
  56. Science - PHYSICS

    im having problem understanding what motion equation to use. " A motercycle moving 12 m/s [W] accelerates at 6.0 m/s [W]. How long will it take to experience a displacement of 63 m [w] ? "
  57. Physics

    consider a cart being pulled up an inclined plane by a student during a Physics lab. The applied force on the cart is 18 N is directed parallel to the incline to cause the cart to be displaced parallel to the incline for a given displacement of 0.7 m. The
  58. Physics

    consider a cart being pulled up an inclined plane by a student during a Physics lab. The applied force on the cart is 18 N is directed parallel to the incline to cause the cart to be displaced parallel to the incline for a given displacement of 0.7 m. The
  59. Physics repost please check

    Posted by Mary on Monday, November 5, 2007 at 8:19pm. A charged particle, passing through a certain region of space, has a velocity whose magnitude and direction remain constant. (a) If it is known that the external magnetic field is zero everywhere in
  60. physics

    Biophysics strikes back The Biophysics students are having their usual Saturday night biophysics party performing physics experiments at a classmate’s home. This Saturday it is in an apartment building and you notice a managemnt student (MS) passed out
  61. Physics please check repost

    The pressure and volume of a gas are changed along a path ABCA in the figure. The vertical divisions on the graph represent 4.0 x 10^5 Pa, and the horizontal divisions represent 4.5 x 10^-3 m3. The diagram is a upright rectangle divided into small squares
  62. Physics please clarify

    A charge of -3.00 µC is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.135 m). The charges on the circle are -3.20 µC at the position due north and +5.00 µC at the position due east. What is
  63. physics

    A physics student pulls a block of mass m = 23 kg up an incline at a slow constant velocity for a distance of d = 4 m. The incline makes an angle q = 25° with the horizontal. The coefficient of kinetic friction between the block and the inclined plane is
  64. Physics

    A certain number of identical resistors are connected in series and their total resistance is measured. When the resistors are disconnected and re-connected in parallel, their total resistance drops to one-percent of the value measured when they were
  65. physics

    A physics student pulls a block of mass m = 20 kg up an incline at a slow constant velocity for a distance of d = 4.5 m. The incline makes an angle Δ = 30° with the horizontal. The coefficient of kinetic friction between the block and the inclined
  66. physics

    A pump slowly lifts 3.0*10^6 kg of water an average distance of 80.0m in 12minutes. 1) how much work is done in the first 12 minutes? 2)How much power is delivered by the pumps?
  67. Physics

    What is the wavelength of a radar signal that has a frequency of 30 GHz? The speed of light is 3 × 10^8 m/s. Answer in units of m Giving me the formula is just fine
  68. Physics

    A bicycle with tires 64 cm in diameter travels 5.2 km . Part A How many revolutions do the wheels make? Express your answer using two significant figures.
  69. physics

    a gazelle attempts to leap a 2.1m fence. assuming a 45 degree takeoff angle, whats the min speed for the jump
  70. physics

    At a construction site a pipe wrench struck the ground with a speed of 24 m/s. (a) From what height was it inadvertently dropped? (b) How long was it falling?
  71. physics

    If two wires P and O each of the same length and same material,are connected in parallel to a battery. The diameter of P is half that of Q. What fraction of the total current passes through P?(a)0.2(b)0.25(c)0.33(d)0.5
  72. Physics

    a 35 kg child slides down a 26 degree incline. the coefficient of kinetic friction is 0.33. what is her speed after sliding for 2.5 seconds starting from rest?
  73. Physics

    Suppose that two concentric rings, each with equal mass per unit length are joined so that they rotate together. Find the moment of inertia.
  74. physics

    What net torque is required to give a uniform 12-kg solid ball with a radius of 0.22m an angular acceleration of 12rad/s2 ?
  75. physics

    describe the force board experiment to show how to obtain the resultant of two non-parallel coplanar forces acting at a point.
  76. physics

    an object weighs 10N on earth .what is the objects weight on a planet one tenth the earths mass and one half its radius?
  77. physics

    If the coefficient of kinetic friction is 0.25 , how much horizontal force is needed to pull each of the following masses along a rough desk at a constant speed? A) 25 kg
  78. physics

    How much work must be done to roll a metal safe, mass 116 kg, a distance of 15.0 m across a level floor? The coeffecient of friction is 0.050.

  80. physics

    a d'arsonval meter movement deflects to 0.8mA. what is the peak value of the alternating current if the instrument uses full-wave rectification?
  81. Physics

    A car whose brakes are locked skids to a stop in 200 ft from an initial velocity of 50 mi/hr. Find the coefficient of sliding friction.
  82. Physics - Help!!!

    I want to be sure I'm using the right formula for this question: Calculate the electric force between 2 electrons that are 5.3 x 10^-11 m apart (electron charge = -1.6 x 10^-19 C) I'm using the equation for Coulomb's Law: F = K (q1 q2)/d^2 (-1.6 x
  83. Physics

    Two positive charges one 2uc and the other 7uc are separated by a distance of 20cm, what is the magnitude of the electrostatic force that each charge exerts upon the other
  84. Physics

    A little girl is standing on a cliff and throws a ball straight down at a speed of 5m/s towards the ground below. How far has it fallen 2.0 seconds after it leaves her hand?
  85. physics

    an object is placed 10 cm from a concave spherical mirror whose radius of curvature is 12 cm. What is the distance of image a) 5cm b) 10 cm c)15cm d)20cm e)24cm
  86. physics

    a car cover 100 m in 5th second and 120 m in 8th second during its motion ?calculate the acceleration and distance covered in 20th second?
  87. physics

    A battery of emf and negligible internal resistance is connected to two resistances R1 and R2 in series. What is the potential difference across R2?(a)E(R1+R2)/R2(b)E(R1+R2)/R1(c)ER2/R1+R2(d)ER1/R1+R2
  88. Physics

    The coefficient of kinetic friction for a 22 kg bobsled on a track is 0.15. What force is required to push it down a 6.0° incline and achieve a speed of 64 km/h at the end of 75 m?
  89. physics

    what is the magnitude and the direction of an electric field when an electron is accelrated vertically upward at a distance of 5.5 metres in 3 micro seconds?
  90. physics

    If Joe rides south on his bicycle in a straight line for 26 min with an average speed of 11.6 km/h, how far has he ridden? Answer in units of km

  92. physics

    Calculate the current that moves through your fingers (resistance 1000 \Omega) when you touch them to the terminals of a 6.4- V battery. please include the units
  93. Physics

    A triply ionized beryllium atom (Be3+) has only one electron in orbit about the nucleus. What is the radius of the ion when it is in the n = 9 excited state?
  94. physics

    Scalar product of three vectors? Given:A=(axi+ajy+azk) B=(bxi+bjy+bzk) C=(cxi+cjy+czk)
  95. physics

    A man whose mass is 75kg walks up a flight of 12 steps each 20 cm high in 5 seconds . Find the power he develops in watts
  96. Physics

    The power output of an elevator is 15000 W. How many persons could it carry if it raises passenger to a height of 35 m in 20 s ( each person has an average mass of 60 kg)?
  97. physics

    A racing car has a mass of 1970 kg. The acceleration of gravity is 9.8 m/s^2. What is its kinetic energy if it has a speed of 102 km/h? Answer in units of J.
  98. physics

    1. During storm roof of house is blown off 2.It is dangerous to stand near the railway track when a train is moving with high speed
  99. Help- Physics

    How much work did the movers do (horizontally) pushing a 130kg crate 10.1 m across a rough floor without acceleration, if the effective coefficient of friction was 0.50?
  100. Physics

    A player kicks a football from ground level with a velocity of magnitude 31.0 m/s at an angle of 30.0 degrees above the horizontal. What is its maximum height?