1. Physics

    Why can you exert a greater force on the pedals of a bike if you pull up on the handlebars? Does it have anything to do with one of Newton's 3 laws? I'm not sure how to approach this question.
  2. Science

    Nathalie pushes on the pedals of his bike with a 320N force. If the bike has a produced force of 640N, what is the mechanical gain of the bike?
  3. physics

    If each complete revolution of the pedals moves the bike 5.00m along its path, calculate the average force that must be exerted on the pedals tangent to their circular path. Neglect work done by friction and other losses. The pedals turn in a circle of
  4. physics

    Assume a cyclist of weight mg can exert a force on the pedals equal to 0.90 mg on the average. If the pedals rotate in a circle of radius 18 cm, the wheels have a radius of 34 cm, and the front and back sprockets on which the chain runs have 42 and 19
  5. physics and bicycles

    I have aq uick question about bicycles relating to physics. I hope you can understand this! First (technical question) why don't bikes move backward when you pedal backward? On to the physics. A string is tied to a bike enabling one to pull the pedal from
  6. Physics

    A cyclist intends to cycle up a 7.5 degree hill whose vertical height is 170 m. Assuming the mass of bicycle plus cyclist is 95 kg, calculate how much work must be done against gravity. If each complete revolution of the pedals moves the bike 5.6 m along
  7. Math

    In lowest gear on a 10-speed bike, each turn of the pedals makes the wheels turn 3.4 times. In the highest gear, each turn of the pedals makes the wheels turn 1.8 times. With each turn of the wheels, the bike travels 6.5 feet. How much farther does the
  8. physics

    there are 3 parts to my question. i need help on the last part. 1.a. A child rides a bike in a circular path with a radius of 2.0 m. The tangential speed of the bike is 2.0 m/s. The combined mass of the bike and the child is 43 kg. What is the magnitude of
  9. Physics

    In the nail puller shown in the figure below you exert a force 49.6 cm from the pivot and the nail is 1.90 cm on the other side. What minimum force must you exert to apply a force of 1460 N to the nail to pull the nail up?
  10. physics

    In the nail puller shown in the figure below you exert a force 53.2 cm from the pivot and the nail is 1.50 cm on the other side. What minimum force must you exert to apply a force of 1380 N to the nail to pull the nail up?
  11. Physics

    A woman holds a 1.9 m long uniform 5.5 kg pole as shown in the figure . her hands are 30 cm apart. Determine the magnitudes of the forces she must exert with each hand. To what position should she move her left hand so that neither hand has to exert a
  12. physics

    A woman holds a 1.9 m long uniform 5.5 kg pole as shown in the figure . her hands are 30 cm apart. Determine the magnitudes of the forces she must exert with each hand. To what position should she move her left hand so that neither hand has to exert a
  13. physics

    A boy exerts a horizontal force of 2nt to pull his 2kg sled over the snow. If he gives someone a ride on his sled and he has to exert a 12nt force to pull the sled, how much does that person weigh and what is their mass?
  14. physics

    the nail puller shown in the figure below you exert a force 53.2 cm from the pivot and the nail is 1.50 cm on the other side. What minimum force must you exert to apply a force of 1380 N to the nail to pull the nail up? 38.9 N is correct What is the
  15. physics -jumper

    The feet of a standing person of mass m exert a force equal to mg on the floor, and the floor exerts an equal and opposite force upwards on the feet, which we call the normal force. During the extension phase of a vertical jump, the feet exert a force on
  16. Math

    If you are riding a bike and your front sprocket (the one with the pedals) has 40 teeth and the rear sprocket (the one connected to your back tire) has 20 teeth, and you are pedaling at a rate of 50 rpm, how fast are you going if your bike has 27 inch
  17. physics

    A locomotive pulls a series of wagons. Which is the correct analysis of the situation? A. because action always equals the reaction,the locomotive cannot pull the wagons,-the wagons pull backward just as hard as the locomotive pulls forward, so there is no
  18. Physics

    For a winter fair, some students decide to build 30.0- kg wooden pull-carts on sled skids. If two 90.0- kg passengers get in, how much force will the puller have to exert to move the pull-cart? The coefficent of maximum static friction between the cart and
  19. Physics

    You want to use a rope to pull a 12-kg box of books up a plane inclined 30∘ above the horizontal. The coefficient of kinetic friction is 0.29. The rope pulls parallel to the incline. What force do you need to exert on the rope if you want to pull the
  20. physics

    . Two people pull on a stubborn mule, as seen from a helicopter in Figure 2.1. Find (a) the single force that is equivalent to the two forces shown, and (b) the force that a third person would have to exert on the mule to make the net force equal to zero.
  21. Physics

    A woman holds a 1.90-m-long uniform 5.0-kg pole as shown in (Figure 1) ( its horizontal). A. Determine the force she must exert on the pole at A. Express your answer to two significant figures and include the appropriate units. Enter positive value if the
  22. science

    You are standing stationary along the side of the railroad tracks. A toy cannon shoots a baseball at 9 m/s. The cannon is mounted facing forward on the handlebars of a bike. Your friend is riding the bike from the front toward the back of a train car at 5
  23. physics

    When you try to walk too fast on a slippery floor, you slip because walking fast requires you to exert a greater frictional force against the floor than the surface allows. What is the maximum frictional force you can exert against the floor with one foot
  24. physics

    A cyclist is riding in the positive horizontal direction at 14.8 m/s on a horizontal level surface. He encounters an air resistance force of 50 N. The actions on the pedals by the cyclist cause a backward force of 73 N to be exerted by the rear wheel on
  25. physics

    A bicycle has wheels 67.3 cm in diameter and pedal cranks 17.5 cm long. The cyclist pedals at a steady cadence of 76.0 rev/min. The chain engages with a front sprocket 15.2 cm in diameter and a rear sprocket 7.00 cm in diameter. Calculate: a) the speed of
  26. physics

    lots of questions 1) a 2N and 6N force pull on an object to the right and a 4N force pulls to the left a 0.5 kg object what is the net force on the object 2)a 20mkg bike accelerates at 10m/s2 with what force was the person pedaling 3)if a person is pushing
  27. physics- please help

    World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s^2 . Part a)How much horizontal force F must a sprinter of mass 60kg exert on the starting blocks to produce this
  28. Math

    A bike is in fourth gear. When the pedals turn 3 times, the rear wheel turns 7 times. When the pedals turn twice, how many times does the rear wheel turn?
  29. Physics

    James Bond and the ever present bond girl are on a dirt bike escaping from a car load of bad guys. If we have the following conditions: James Bond’s mass is 84 Kg The Bond Girl is 48Kg The Dirt Bike’s mass is 113.6 Kg The tires on the dirt bike are
  30. physics

    Which of the following does not involve a force? a.tug of war b.pushing a wagon c.riding a bike d.jumping e.None of the above f.towing a car g.hitting a ball Is the answer e. none of the above? I know a,b,c,d, and g exert a force, but I am not sure about
  31. Physical science

    Why don't you move when you pull a door open and the force the door exerts on you is equal to the force you exert on the door?
  32. Science

    You pull a door open. If the force the door exerts on you is equal to the force you exert on the door, why don't you move?
  33. Physics

    d. Now you pull your sister across the floor so that she moves with increasing speed (accelerates). Compare the magnitude of the force exerted by you on your sister, with the magnitude of the force she exerts on you. Are they the same or different? If they
  34. Physics

    - a 1200 W motor bike can move at a maximum speed of 30.0 m/s . how much force does the motor exert? - what would be the average momentum of 60.0 kg sprinter who finishes 100.0 m in 60 s?
  35. physics

    a person weights 550 N rides a bike. the pedals move in a circle of radius 30 cm. if the entire wt acts on each downward moving pedal, what is maximum torque
  36. Physics

    Suppose your car was mired deeply in the mud and you wanted to use the method illustrated in the figure to pull it out. T = 11000 N A. What force would you have to exert perpendicular to the center of the rope to produce a force of 11000 N on the car if
  37. Physicis

    Given: Two teams of children are well-matched, and they pull on the rope with exactly the same force. They have placed a 65n weight at the center of the rope. The teams first pull with 750n of force each, then in an heroic effort to straighten the rope,
  38. Physics

    Hello everyone I know that when a force is applied it has to exert a force opossite But this really is not in my head can someone please give me an evidence or even a diagram showing how can we exert an opposite force if we are walking forwards Thanks alot
  39. Physics

    Suppose your car was mired deeply in the mud and you wanted to use the method illustrated in the figure to pull it out. (a) What force in newtons would you have to exert perpendicular to the center of a rope to produce a force of 10,000 N on the car if the
  40. PHYSICS-Net external Force

    1. Two tugboats pull a barge across the harbor. one boat exerts of force of 7.5 x 10^4 N North, while the second boat exerts a force of 9.5 x 10^4 N at 15.0 degrees north of west. Precisely, in what direction does the barge move? 2. A traffic signal is
  41. Science

    if you exert the same force on two objects of different masses. which object will have the greater acceleration?
  42. Physics

    Two people pull a mule. One with 120 Newtons and an angle of 60 degrees. The other with 80 N and an angle of 105 degrees (Q2). What would be the force a third person would have to exert on the mule to make the net force equal to zero.
  43. sceinc

    you exert the same force on two objects of different masses .whitch object will have greater acceleration
  44. physics

    If you exert a force of 60 N on a car, it moves at a constant velocity. (i.e there is a frictional force of 60 N) What is its mass when you exert 80 N on it, it accelerates from rest to 2.0 m/s in 100 seconds?
  45. physics

    two charged bodies exert a force of 86N on each other. If they are moved so that they are 6 times farther apart, what is the new force that they will exert on each other?
  46. science

    How would i set these up? like what is the equations? # A tennis player hits a tennis ball with a force of 330 N, and it accelerates at the rate of 5,500 m/s2. What is the mass of the tennis ball? # Li is pedaling his bike with a force of 220 N. The
  47. Physics

    Suppose your car was mired deeply in the mud and you wanted to use the method illustrated in the figure below to pull it out. (a) What force would you have to exert perpendicular to the center of a rope to produce a force of 14,500 N on the car if the
  48. Phsics

    A crate weighing 600. N is being pulled across the floor. You pull up and to the right on a rope which is attached to the crate. You exert a force of 155 N at an angle θ=29.0° above the horizontal.
  49. physics

    two tractors pull against a 1000 kg log. if the angle of the tractors chains in relation to each other is 18 degrees and each tractor pulls with a force of 800N what forces will they be able to exert
  50. drwls please read

    i know this might seem kind of long. but if you could please help me, i'd greatly appreciate it. a. suppose you have a tug of war with a friend who is the same size and weight as you are. You both pull as hard as you can, but neither of you seems to be
  51. Science

    Explain: You pull a door open. If the door exerts on you is equal to the net force you exert on the door, why don't you move?
  52. AP Physics

    A cord runs around two massless, frictionless pulleys; a canister with mass m=20 kg hangs from one pulley; and you exert a force F if you are to lift the cord. a) What must be the magnitude of F if you are to lift the canister at a constant speed? b) To
  53. Physics

    Imagine a fender bender between a large truck and a small car. During the impact, Choose one answer. a. the truck exerts a greater amount of force on the car than the car exerts on the truck b. the car exerts a greater amount of force on the truck than the
  54. Physics

    Two Kids pull opposite directions on a toy with a mass of 18kg. One exerts a force of 695N and the other 135N. Both pull horizontally and friction is void. Calculate the new force in N?
  55. anatomy

    do you think there is a difference in the absolute force generated by males and females? I think the answer is yes just by the common knowledge that males are typically stronger than women. But, I'm not sure how to scientifically explain why a man's
  56. Physics

    You exert a 100-N pull on the end of a spring. When you increase the force by 20% to 120 N, the spring's length increases 4.0cm beyond its original stretched position. What is the spring constant of the spring?
  57. Math

    The local park has 4 bike rack. Each bike rack can hold 15 bikes. There are 16 bike in the bike rack. What expression shows the total number of empty spaces in the bike racks?
  58. physics

    1. A 50.0 Lb box is to be moved along a rough floor at a constant velocity. The coefficient of the kinetic friction is 0.300. A. What force must you exert if you push downward on the box? B. What force must you exert if you pull upward on the box? C. Which
  59. Physics

    A bike is hanging from a hook in a garage. You need to consider the following forces. (a) The force of the Earth pulling down on the bike. (b) The force of the bike pulling up on the Earth. (c) The force of the hook pulling up on the bike. (d) The force of
  60. Physics

    A bike is hanging from a hook in a garage. You need to consider the following forces. (a) The force of the Earth pulling down on the bike. (b) The force of the bike pulling up on the Earth. (c) The force of the hook pulling up on the bike. (d) The force of
  61. Science

    Why does the downhill-race bike look the way it does and what magnitude of force and any dynamic loads effect the bike. please help
  62. science

    While riding a bike, a rider exerts a force of 540 N on the pedal, which when attatched to a sprocket creates a radius of rotation of 0.18 m. How much torque does the rider exert on the sprocket? I think I have to use the formula torque=rFsin(x) But I'm
  63. Physics

    You exert a horizontal force of 200 N to pull a 10-kg box across the floor. If the coefficient of kinetic friction between the box and the floor is .42, what is the acceleration of the box?
  64. physics

    a strong magnet attracts a paper clip to itself with a certain force. Does the paper clip exert a force on the strong magnet? If so, why not? If so, does it exert as much force on the magnet as the magnet exerts on it? Newtons Third Law: Forces are always
  65. Physics

    You exert a force of 200 N at an angle of 15 degrees above horizontal to pull a 10 kg box across the floor at constant velocity. If the coefficient of kinetic friction between the box and the floor is 0.42, what is the acceleration of the box?
  66. Physics

    Three people pull horizontally on ropes attached to a post, as shown in the figure.(Figure 1) The total force that they exert on the post is zero. One of them pulls directly north with F1 = 500 N . Another pulls with F2 = 400 N in a direction 60.0∘
  67. Physics

    Calculate the force of gravity between a newborn baby of mass 4 kg and the obstetrician of mass 75 kg, who is 0.5 m from the baby. N Which exerts more gravitational force on the baby, Mars or the obstetrician, given that Mars has a mass of 6.4 1023 kg and
  68. physics

    A 57.0 kg child takes a ride on a Ferris wheel that rotates four times each minute and has a diameter of 23.0 m. (a) What is the centripetal acceleration of the child? (b) What force (magnitude and direction) does the seat exert on the child at the lowest
  69. physics

    A bike is hanging from a hook in a garage. Consider the following forces. (a) The force of the Earth pulling down on the bike. (b) The force of the bike pulling up on the Earth. (c) The force of the hook pulling up on the bike. (d) The force of the hook
  70. Physics

    Three people pull simultaneously on a stubborn donkey. Jack pulls eastward with a force of 93.3 N, Jill pulls with 73.1 N in the northeast direction, and Jane pulls to the southeast with 181 N. (Since the donkey is involved with such uncoordinated people,
  71. physics

    Three people pull simultaneously on a stubborn donkey. Jack pulls eastward with a force of 67.3 N, Jill pulls with 98.7 N in the northeast direction, and Jane pulls to the southeast with 133 N. (Since the donkey is involved with such uncoordinated people,
  72. Science

    Why does the downhill-race bike look the way it does, what stuff does it have which normal bikes don't and what magnitude of force and dynamic loads effect the bike. please help
  73. Physics

    You are working out on a rowing machine. Each time you pull the rowing bar (which simulates the oars) toward you, it moves a distance of 1.2 m in a time of 1.4 s. The readout on the display indicates that the average power you are producing is 78 W. What
  74. Physics

    You are trying to lose weight by working out on a rowing machine. Each time you pull the rowing bar (which simulates the "oars") toward you, it moves a distance of 1.32 m in a time of 1.22 s. The readout on the display indicates that the average power you
  75. physics

    You are trying to lose weight by working out on a rowing machine. Each time you pull the rowing bar (which simulates the "oars") toward you, it moves a distance of 1.17 m in a time of 1.84 s. The readout on the display indicates that the average power you
  76. physics

    15)If a horizontal force applied on a resting object is greater than the force of friction, the object will. accelerate in the direction of the applied force 16)You are pushing a 55N lawnmower across the yard. Its handle makes a 55 degree angle with the
  77. Math

    in the back stockroom at the wheel shop, the number of seats and horns equaled the number of wheels. the number of seats and handlebars equaled the number of horns. twice the number of wheels is equal to 3 times number of handlebars. Determine the
  78. Physics

    Two lifeguards pull on ropes attached to a raft. If they pull in the same direction, the raft experiences a net external force of 363 N to the right. If they pull in opposite directions, the raft experiences a net external force of 147 N to the left. Draw
  79. physics

    Two lifeguards pull on ropes attached to a raft. If they pull in the same direction, the raft experiences a net external force of 376 N to the right. If they pull in opposite directions, the raft experiences a net external force of 162 N to the left. Draw
  80. PHYSICS

    Two lifeguards pull on ropes attached to a raft. If they pull in the same direction, the raft experiences a net external force of 332 N to the right. If they pull in opposite directions, the raft experiences a net external force of 122 N to the left. Draw
  81. physics

    A 34.2 -kg block rests on the oor. (a) What force (N) does the oor exert on the block? (b) If a rope is tied to the block and run vertically over a pulley, and the other end is attached to a free-hanging 5.6 kg weight, what force (N) does the oor now exert
  82. Physics

    A 75.0-kg cross-country skier is climbing a 3.0o slope at a constant speed of 2.00 m/s and encounters air resistance of 25.0 N. Find his power output for work done against the gravitational force and air resistance. (b) What average force does he exert
  83. Physics

    A 75.0-kg cross-country skier is climbing a 3.0o slope at a constant speed of 2.00 m/s and encounters air resistance of 25.0 N. Find his power output for work done against the gravitational force and air resistance. (b) What average force does he exert
  84. physics

    a 50 kg crate is at rest on a level surface the coefficients of friction are 0.3 and 0.4,what is the normal force acting on the crate, a man begins pushing horizontally on the crate how much force must the man exert to start the crate moving, how much
  85. physics

    A woman pulls a 23 kg suitcase using a rope attached to the suitcase at an angle of 38 degrees to the horizontal. The coefficient of static friction of the suitcase with the floor is 0.3 and the coefficient of kinetic friction is 0.2. a) Draw a situation
  86. Physics

    An engine is used to pull a train of two cars out of a mine. The floor slopes upward at an angle of 24o. Each car has a mass of 0.8x104 Kg and normally travels without friction on the tracks. The engine can exert a maximum force of 1.4x105 N on car A. If
  87. Calculus

    Okay so I have the following question and I am totally stuck: Newton's Law of Gravitation says that the magnitude F or the force exerted by a body of mass m on a body of mass M given by F=(GmM)/r^2 where G is the gravitational constant and r the distance
  88. physics

    A cat is stuck in a tree. You are designated with the job to get it out, yet you do not want to climb the tree, because you may get stuck as well. Instead you set up a pulley system. A rope (consider it massless) runs from the seat you sit on over an ideal
  89. physics

    1. A small railroad engine is able to exert 8•105 N of pulling force. The coefficient of friction for steel wheels on steel rail is 0.4. Each rail car has the approximate mass of 20 tons How many cars can this engine pull on a level track?
  90. Science

    A boy exerts a force of 15N to push a motor bike which has flat tyre for a distance at 30m.calculate the mass of the motor bike. Calculate the density of the motor bike.calculate the work done by the boy.[take g=10m|sm2
  91. Science

    A boy exerts a force of 15N to push a motor bike which has flat tyre for a distance at 30m.calculate the mass of the motor bike. Calculate the density of the motor bike.calculate the work done by the boy.[take g=10m|sm2
  92. Physics

    In a phsics experiment, a 1.3 kg dynamics cart is placed on a ramp inclined at 25 degrees to the horizontal. the cart is initially at rest but is then pulled up the ramp with a force sensor. the force sensor exerts a force on the cart parallel to the ramp.
  93. Physics

    In a phsics experiment, a 1.3 kg dynamics cart is placed on a ramp inclined at 25 degrees to the horizontal. the cart is initially at rest but is then pulled up the ramp with a force sensor. the force sensor exerts a force on the cart parallel to the ramp.
  94. Physics

    Two 2.160 kg crystal balls are 0.870 m apart in the vertical direction. Calculate the magnitude of the gravitational force they exert on a 8.80 g marble located 0.260 m horizontally out from the center of a line that intersects the centers of the balls.
  95. Precalc 2

    At a state fair truck pull, two pickup trucks are attached to the back end of a monster truck as illustrated in the figure. One of the pickups pulls with a force of 1600 pounds and the other pulls with a force of 3200 pounds with an angle of 45° between
  96. Physics

    How much force does an 88 kg astronaut exert on his chair while sitting at rest on the launch pad? Answer: 860N Now the question: How much force does the astronaut exert on his chair while accelerating straight up at 14 m/s^2? What do you do first, how do
  97. Physical Science

    A cyclist applies a force of 250 N to the pedals of a bicycle. If the rear wheel applies a force of 200 N to the road surface. What is the mechanical advantage of the bicycle?
  98. Mechanics & hydromechanics

    Find the magnitude and direction of the equilibrant of two forces, one being horizontal pull of 18 N and the other a pull of 23 N at 50 degrees to the 12 N force.
  99. Mechanics & hydromechanics

    Find the magnitude and direction of the equilibrant of two forces, one being a horizontal pull of 18 N and the other a pull of 23 N at 50 degrees to the 12 N force.
  100. Mechanics....Urgent!!

    Find the magnitude and direction of the equilibrant of two forces, one being horizontal pull of 18 N and the other a pull of 23 N at 50 degrees to the 12 N force.