1. Physics - gravitational acceleration

    How does and Atwood machine make it easier to determine g - the acceleration due to gravity, rather than by just measuring the acceleration of a free-falling object?
  2. Physics/Math

    The Formula you use is the correct one. However, consider this. If the initial PE existed, wouldn't you have to add it to the initial KE then subtract the PE at some R from the center? We normally make ground zero PE level, but for this... Zero, a
  3. physics

    Two ping pong balls each have a mass of 1.4 grams and carry a net charge of 0.450uC. one ball is held fixed. at what height should the second ball be placed directly above the fixed ball if it is to remain at rest there?
  4. Physics

    Two ping-pong balls each have a mass of (1.4x10^0) g and carry a net charge of (3.99x10^0) μC. One ball is held fixed. At what height should the second ball be placed directly above the fixed ball if it is to remain there?
  5. Physics

    Astrology, that unlikely and vague pseudoscience, makes much of the position of the planets at the moment of birth. The only known force a planet exerts on earth is gravitational. (a) Calculate the gravitational force exerted on a 4.00 kg baby by a 90 kg
  6. Physics (Liquids)

    I have a question about fluids ok... I've been told that Pressure = (density of fluid) (gravity) (height) ok that's great in all but I don't see how it works... Pressure = (Force perinduclar to area force is acting on)/(Area force is acting on) ok this
  7. Physics

    A ball rolls down a hill with a constant acceleration of 2.0 m/s2. If the ball starts from rest, (a) what is its velocity and the end of 4.0 s? (b) How far did the ball move?
  8. Physics

    A ball is rolling on a track with an intial velocity of 2.0m/s, E. If the acceleration is 1.5 m/s2, write a sentence that describes the ball's motion, i.e, what does the ball do each second?
  9. Physics

    A ball rolls down a hill with a constant acceleration of 2.0 m/s2. If the ball starts from rest, (a) what is its velocity and the end of 4.0 s? (b) How far did the ball move?
  10. physics

    If we were to find advanced life on a planet which orbited reasonably near to a star of temperature 30000 Kelvin, to what wavelength of radiation (measured in nanometers, nm) might we reasonably predict their eyes would be most sensitive?
  11. English

    I need the following books in audios I can't find any could someone help please :) 1. Borders by Thomas King 2. Delfino II: diez in the Desert by Sam Quinones 3. Hip-Hop Planet by James McBride
  12. Math

    If a hypothetical planet in our Solar System had a sidereal period of 11.1 Earth years and a circular orbit, how far from the Sun in Astronomical Units would it be? Enter your answer to the nearest 0.01 AU.
  13. Physics Help!!

    A passenger on an interplanetary express bus traveling at v = 0.94c takes a seven-minute catnap by his watch. How long does the nap last from your vantage point on a fixed planet?
  14. English

    6.) "Then felt like some watcher of the skies/When a new planet swims into his ken..." This excerpt from John Keats's "On First Looking into Chapman's Homer" is an example of a(n) A.) metaphor B.) simile C.) stanza D.) apostrophe Answer: 6.) B Thank you
  15. physics

    gravity on the surface of the moon is only 1/6 as strong as gravity on earth. what is the weight of a 37 kg object on the earth? The acceleration of gravity is 10m/s answer in units of N
  16. Physics

    Gravity on the surface of the moon is only 1 6 as strong as gravity on the Earth. What is the weight of a 33 kg object on the Earth? The acceleration of gravity is 10m/s2 . Answer in units of N.
  17. College Physics

    Gravity on the surface of the moon is only 1/6 as strong as gravity on the Earth. What is the weight of a 14 kg object on the Earth? The acceleration of gravity is 10m/s2 . Answer in units of N.
  18. southeast

    A ball is thrown downward with an initial velocity of 11 m/s. Using the approximate value of g = 10 m/s2, what is the velocity of the ball 1.6 seconds after it is released?
  19. Physics

    You throw a ball downward from a window at a speed of 3.6 m/s. What will the speed of the ball be immediately before hitting the sidewalk 8.3 m below?
  20. PHYSICS

    AN ELECTRIC FIELD 1500N AND MAGNETIC FIELD 0.40T ACT AT A,MOVING PROTRON TO PRODUCE NO FORCE.CALCULATE THE MINIMUM SPEED OF THE PROTRON.
  21. Physics

    In a lightning bolt, a large amount of charge flows during a time of 2.2 10-3 s. Assume that the bolt can be treated as a long, straight line of current. At a perpendicular distance of 28 m from the bolt, a magnetic field of 7.3 10-5 T is measured. How
  22. Physics

    A steel ball is dropped from a building's roof and passes a window, taking 0.13 s to fall from the top to the bottom of the window, a distance of 1.20 m. It then falls to a sidewalk and bounces back past the window, moving from bottom to top in 0.13 s.
  23. astronomy 101

    Given that the angular size of Venus is 53ŒŒ'' when the planet is 47000000kmkm from Earth, calculate Venus's diameter (in kilometers).
  24. Physics

    Planet Jupiter revolves around the Sunin 12 years (3.79 X 10^8 sec. What is its mean distance from center of Sun? mass of sun is 1.99 x 10^30 kg.
  25. Physics - Planetary Motion

    The planet Neptune has an orbital radiu around the sun of about 4.50 * 10^12m. What are its period and its orbital speed?
  26. Physics

    If a small planet were located 7 times as far as the Earth's distance from the Sun, it period is ___ earth years?
  27. physics

    The period of a satellite is independent of a) Its own mass b) The mass of the planet it orbits c) The value of the gravitational constant The orbital d) radius
  28. physics

    An electric charfe of -3 C is moved from a position where the electric potential is 1 V to a position where the electric potential is -6V. What is the chsange in potential energy of the charge with this change in position? I know that change in PE =
  29. physics

    Find the value of the magnetic field necessary to cause a proton moving at a speed of 2.50 ×10^3 m/s to go into a circular orbit of 15.5-cm radius. An electron has an energy of 100 eV as it enters a magnetic field of 3.50 × 10−2 T. Find the radius
  30. Physics

    Gravity on the surface of the moon is only 1 as strong as gravity on the Earth. 6 What is the weight of a 30 kg object on the Earth? The acceleration of gravity is 10 m/s2 . Answer in units of N.
  31. Physics

    A spherical bowling ball with mass m = 3.2 kg and radius R = 0.107 m is thrown down the lane with an initial speed of v = 8.6 m/s. The coefficient of kinetic friction between the sliding ball and the ground is μ = 0.34. Once the ball begins to roll
  32. science

    The electric field intensity between two charged plates is 1.1*10^3 N/C. The plates are 0.070 m apart. What is the electric potential difference, in volts, between the plates?
  33. calculus

    A ball is thrown vertically upwards from a height of 6 ft with an initial velocity of 60 ft per second. How high will the ball go? Note that the acceleration of the ball is given by a(t)= 32 feet per second per second.
  34. science

    A ball is thrown from a height of 10m with certain initial downward velocity. It hits the ground and loses 50% of its energy during the impact and rises back to the sane height. What was its initial downward velocity of projection?
  35. physics

    A positive charge q1 = 2.70 uC on a frictionless horizontal surface is attached to a spring of force constant k as in the figure. When a charge of q2 = –8.60 uC is placed 9.50 cm away from the positive charge, the spring stretches by 5.00 mm, reducing
  36. physics

    The potential diffrence across a series combination of 4(micro)F and 12(micro)F capacitor is 240V. What is the potential diffrence across 4(micro)F capacitor?
  37. science

    the acceleration of gravity on the surface of Mars is m/s squared. if an astronaut in a space suit can jump upward 20cm on the earth's surface, how high could he jump on the surface of Mars? You need to provide a number for the acceleration of gravity on
  38. Physics

    A small cork with an excess charge of +6.0 µC is placed 0.25 m from another cork, which carries a charge of −3.2 µC. What is the magnitude of the electric force between the corks? The Coulomb constant is 8.98755 × 10 9 N · m2 /C 2 . Answer in
  39. physics

    A small cork with an excess charge of +7.0 µC is placed 0.16 m from another cork, which carries a charge of −3.2 µC. What is the magnitude of the electric force between the corks? The Coulomb constant is 8.98755 × 10 9 N · m2 /C 2 . Answer in
  40. Physics

    I got two questions Three blocks on a fricitonless horizontal surface are in contact with each other a force F is applied to block 1 mass m1 Draw a free body diagram for each block ok done the accelration of the system (in terms of m1, m2, and m3) ok done
  41. Physics

    An airplane is flying above the Earth's surface at a height of 10.9 km. The centripetal acceleration of the plane is 16.7 m/s2. What is the angular velocity of the plane moving in uniform circular motion? Take the radius of the earth to be 6400 km.
  42. physics

    An airplane is flying above the Earth's surface at a height of 9.30 km. The centripetal acceleration of the plane is 18.2 m/s2. What is the angular velocity of the plane moving in uniform circular motion? Take the radius of the earth to be 6400 km.
  43. physics

    An airplane is flying above the Earth's surface at a height of 10.5 km. The centripetal acceleration of the plane is 16.4 m/s2. What is the angular velocity of the plane moving in uniform circular motion? Take the radius of the earth to be 6400 km.
  44. Science

    Please check my answers? My textbook won't load, so i've had to use google and guess. 1. Scientists hypothesize that the sun formed ____. (1 point) less than a billion years ago **from a cloud of gas and dust less than a million years ago from a chunk of
  45. physics

    A boy can throw a ball a maximum horizontal distance of R on a level field. How far can he throw the same ball vertically upward? Assume that his muscles give the ball the same speed in each case. (Use R and g as appropriate in your equation.)
  46. physics

    A boy can throw a ball a maximum horizontal distance of R on a level field. How far can he throw the same ball vertically upward? Assume that his muscles give the ball the same speed in each case. (Use R and g as appropriate in your equation.)
  47. physics

    A boy can throw a ball a maximum horizontal distance of R on a level field. How far can he throw the same ball vertically upward? Assume that his muscles give the ball the same speed in each case. (Use R and g as appropriate in your equation.)
  48. physics

    A boy can throw a ball a maximum horizontal distance of R on a level field. How far can he throw the same ball vertically upward? Assume that his muscles give the ball the same speed in each case. (Use R and g as appropriate in your equation.)
  49. Astronomy

    Black holes can be completely described by which three parameters? -angular momentum, spin, and electric charge -angular momentum, density, and radius -mass, angular momentum, and electric charge -mass, angular momentum, and radius
  50. Physics

    Newton's second law states that if an object has zero acceleration, the net force acting on it is zero. My question is if you have an object at constant acceleration moving downward is there a net force being applied to it? Does constant acceleration= zero
  51. h.s. physics

    Consider a projectile that is thrown upward at an angle between 10 and 80 degrees from the horizontal, when are the acceleration and velocity vectors perpendicular to each other? (Only consider the motion during free fall.) a) nowhere b)at the highest
  52. Math, Trig

    A soccer player kicks a ball from the ground to a maximum height of 12 m. The high point in the trajectory of the ball occurs at a distance of 18 m from the kicker. On the downward path, another player heads the ball at a height of 2.2 m from the ground.
  53. Physics

    An electron enters a region of space where the potential difference between two equipotential surfaces are 12 cm apart. One surface has a potential of 120 volts and the other potential of 75 volts. What is the magnitude and direction of the electric field
  54. physics

    A fast, measured pitched baseball left the pitcher's hand at a speed of 49.0 m/s. The pitcher was in contact with the ball over a distance of 1.59 m and produced constant acceleration. (a) What acceleration did he give the ball?
  55. AP Physics

    Hi! I'm supposed to derive an algebraic formula to solve for the acceleration using one of the linear kinematics formulas of an elevator with a person inside that begins to accelerate from rest moving downward. If it travels a know distance, d, in reaching
  56. College Physics II

    An electric field of 2.04 kV/m and a magnetic field of 0.548 T act on a moving electron to produce no net force. If the fields are perpendicular to each other, what is the electron's speed?
  57. physics

    Two students are on a balcony 21.4 m above the street. One student throws a ball ver- tically downward at 15.6 m/s. At the same instant, the other student throws a ball verti- cally upward at the same speed. The second ball just misses the balcony on the
  58. Physics

    The tension on a string from which a 5.00kg object is suspended in an elevator is T=(44.0j)N. What is the acceleration of the elevator? Specify the acceleration in unit vector notation. T - Mg = M a with positive force upward. a = T/m - g = 8.8 - 9.8 =
  59. Physics

    In a fast-pitch softball game the pitcher is impressive to watch, as she delivers a pitch by rapidly whirling her arm around so that the ball in her hand moves in a circle. In one instance, the radius of the circle is 0.622 m. At one point on this circle,
  60. physics

    An electron has a kinetic energy of 4.2 x 10-17 J. It moves on a circular path that is perpendicular to a uniform magnetic field of magnitude 3.3 x 10-5 T. Determine the radius of the path. The electron in the problem has Charge of the electron (q) =
  61. Physics

    Note: The left-hand mass is equal to the sum of the other two masses. A massless pulley is attached to the ceiling,in a uniform gravitational field, and rotates with no friction about its pivot. Another massless pulley is attached to the end of the cord on
  62. Physics Honors

    A pool ball leaves a 0.60 meter high table with an initial velocity of 2.4 m/s. Predict the time required for the pool ball to fall to the ground and the horizontal distance between the table's edge and the ball's landing location.
  63. physics

    1.A proton enters a 2.0 X 10^-2 T magnetic field with a speed of 5.8 X 10^4 m/s. What is the radius of the circular path it follows? formula?? 2.Electrons moving at 3.5 X 10^4 m/s pass through an electric field with an intensity of 5.6 X 10^3 N/C. How
  64. Physics

    A 2.5kg solid homogenous ball is rolling without slipping at 3.0 meters per second to the right on a level surface. The diameter of the ball is 80 centimeters. What is the total kinetic energy of the ball? Can someone give me the equation for this?
  65. physics

    A 2.5kg solid homogenous ball is rolling without slipping at 3.0 meters per second to the right on a level surface. The diameter of the ball is 80 centimeters. What is the total kinetic energy of the ball? Can someone give me the equation for this?
  66. Physics

    Maria throws a ball straight up with an initial velocity of 10 m/s. What is its velocity at the highest point? What is its velocity when it returned to the elevation from where it is thrown ? What is its acceleration at the highest point? What is its
  67. Physics

    A tennis player hits a ball at ground level, giving it an initial velocity of 24 m/s at 57 degrees above the horizontal. (a) what are the horizontal and verticla components of the ball;s initial velocity? (b) how high above the ground does the ball go? (c)
  68. Physics

    Gravity on the surface of the moon is only 1/6 as strong as gravity on the Earth. What is the weight of a 24 kg object on the Earth? The acceleration of gravity is 10m/s2 .
  69. physics

    (a) Just for fun, a person jumps from rest from the top of a cliff overlooking a lake. In falling through a distance H, she acquires a certain speed v. Assuming free-fall conditions, how much farther must she fall in order to acquire speed 2v? Express your
  70. English

    1. Some of his pictures seem to be close to what's happening now. 2. Some of his pictures seem close to what's happening now. 3. Some of his pictures seem to be close to the thing which is happening now. 4. Some of his pictures seem to be close to the
  71. Physics

    1)Which of the following statements is true about electric forces? A)electric forces cause objects to only attract each other. B)electric forces cause objects to only repel each other C)electric forces cause objects to repel or attract each other
  72. 9th grade

    An uknown substance from planet x has a density of 10g/ml.it occupies a volume of 80ml. what is the mass of this unknown substance
  73. 9th grade

    An uknown substance from planet x has a density of 10g/ml.it occupies a volume of 80ml. what is the mass of this unknown substance
  74. Physics

    an object is punted at 25m/s [40 degrees North of East] on G's home planet. What is the range of the object on level ground? (use g= 18 m/s
  75. science

    Part A Draw a picture of an object that might impact a planet. Part B What evidence is there that these objects collide with planets and moons?
  76. science

    HYPOTHESIZE-mercury is the closest planet to the sun , yet it doesn't reflect much of the suns light. what can you say about mercury's color? Please help.thanks in advance
  77. English

    Choose the best action or situation. An example of a metonym for the planet earth. soil globe rock moon Answer: globe
  78. 3rd grade - Solor System

    How many years does it take Jupiter to orbit the sun? One year on the this planet would actually be how many earth years long?
  79. science

    Should humans be concerned with the extinction rate? And discuss whether or not humans strive to preserve representative samples of all biomes on the planet.
  80. Music

    I want to make a song with the theme of "Planet Earth", although I'm not good at singing, so I'm just looking for a beat song. Can anyone of you suggest a genre or what instruments should I use?
  81. physics

    Calculate the mass of the star using the fact that the period of the planet is 3.07 × 107 s and its distance from the star is 1.26×1011 m. Answer in units of kg
  82. Physics 131

    A -2.72 ìC charge is placed at the center of a conducting spherical shell, and a total charge of +6.35 ìC is placed on the shell itself. Calculate the total charge on the outer surface of the conductor.
  83. Physics

    A ball is thrown upward from the ground with an initial speed of 25 m/s; at the same instant, a ball dropped from rest from a building 15 m high. After how long will the balls be at the same height? The equations I have is final velocity squared = initial
  84. physics

    How much work is done to move 1.0 micro coloumb of charge from the negative terminal to the positive terminal of a 1.8V battery?
  85. Physics

    A point charge of -14nC and +12nC is located 12cm along the x-axis. Determine the magnitude and direction of the electric field intensity at point P at the mid-point and 8cm perpendicular from the x-axis: p | | 8.0cm | | -14nC.---------------. 12 nC 6cm
  86. Math

    If the perimeter of the rectangular ball field is 1 kilometer which of the following could be the field's dimensions? L=312m W=188m or L= 1/2 m W = 1/2 m
  87. Science

    If the perimeter of the rectangular ball field is 1 kilometer which of the following could be the field's dimensions? L=312m W=188m or L= 1/2 m W = 1/2 m
  88. physics

    A small cork with an excess charge of +5.0 ¦ÌC is placed 0.14 m from another cork, which carries a charge of −3.2 ¦ÌC. What is the magnitude of the electric force between the corks? The Coulomb constant is 8.98755 ¡Á 109 N ¡¤ m2/C2. Answer in
  89. physics

    A charge of 8 pC is uniformly distributed throughout the volume between concentric spherical surfaces having radii of 1.7 cm and3.7 cm. What is the magnitude of the electric field 2.6 cm from the center of the surfaces? Let k_e=8.98755*10^9 N*m^2/C^2 I
  90. physics

    How much work does the electric field do in moving a proton from a point with a potential of +120 V to a point where it is -60 V? Express your answer in joules. I've looked through my notes, and I'm sure the answer is really easy, but I'm not seeing it. I
  91. physics

    You exert a force of 325N on the ball and it compresses the spring 44.5cm. ... Charge B (-5.0*10^-6) is at the origin; charge c (+4.0*10^-6) has coordinates (5 ,0),
  92. Physics

    A tennis player hits a ball at ground level, giving it an initial velocity of 24 m/s at 57 degrees above the horizontal. (a) what are the horizontal and verticla components of the ball;s initial velocity? (b) how high above the ground does the ball go? (c)
  93. physics

    A ball is thrown horizontally at 10.0 m/s from the top of a hill 50.0 m high. How far from the base of the hill would the ball hit the ground? I don't understand the following explained by Quittich (sp)? "Since there is no vertical component, the time to
  94. college physics

    Consider a projectile that is thrown upward at an angle between 10 and 80 degrees from the horizontal, when are the acceleration and velocity vectors perpendicular to each other? (Only consider the motion during free fall.) a) nowhere b)at the highest
  95. Science ; Micro-organisms

    i have to finished this cross word , and i need help on the last two . So thank you if you can solve it :) A substance that micro organisms can be grown on . its a 4 letter word. A group Of Micro Organisms , its a 6 letter word.
  96. College Physics

    During an electrical storm, clouds can build up very large amounts of charge, and this charge can induce charges on the earth's surface. Sketch the distribution of charges at the earth's surface in the vicinity of a cloud if the cloud is positively charged
  97. Physics

    A rock is thrown vertically upward with a speed of 11.0 m/s from the roof of a building that is 70.0 m above the ground. Assume free fall. In how many seconds after being thrown does the rock strike the ground? GOT THIS!!!! t=5.07s What is the speed of the
  98. physics

    A placemaker must kick a football from a point 36 m (about 39yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a velocity of 20.0 m/s at an angle 53 degrees to the horizontal. By how
  99. physics

    A placemaker must kick a football from a point 36 m (about 39yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a velocity of 20.0 m/s at an angle 53 degrees to the horizontal. By how
  100. Physics

    An electron is at rest. Can this electron be set into motion by applying a) a magnetic field? b) an electric field? Explain your answers. I know that that one of the fields can only be caused by movement, but I don't remember which one...