physics

The weightless horizontal bar in the figure below is in equilibrium. Scale B reads 4.00 kg (N.B. as you know, the scale should read N, but no one told the manufacturer). The distances in the figure (which is not to scale) are: D1 = 9.0 cm, D2 = 8.0 cm, and D3 = 6.5 cm. The mass of block X is 0.96 kg and the mass of block Y is 1.93 kg.

  1. 👍
  2. 👎
  3. 👁
  1. without the figure, I have no idea what the distances mean.

    1. 👍
    2. 👎
    👤
    bobpursley
  2. I believe that I know this figure.
    If it is so, then...
    Let's examine the torques. The torque on A must equal the torque on B
    since the system is at rest. The torque on B can be found by summing the
    torques from mass x and mass y. Since mass z is on the axis of rotation (at B),it produces no torque.
    M(B) = (D2 + D3) •m(x) + D3•m(y),
    The torque on A can be calculated by referencing it from B. In other words,
    what torque must be applied at A to counteract the torques from m(x) and m(y)? This can by found by denoting the variable m(A) to represent the mass (the scale reading) at A to counteract the torque calculated above. That is,

    m(A)•(D1+D2+D3) = (D2 + D3) •m(x) + D3•m(y),

    Thus, the scale reading at A, that is, m(A)

    m(A) = [(D2 + D3) •m(x) + D3•m(y)]/ (D1+D2+D3)

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Physics Classical Mechanics

    A bar of mass m and negligible height is lying horizontally across and perpendicular to a pair of counter rotating rollers as shown in the figure. The rollers are separated by a distance D. There is a coefficient of kinetic

  2. Physics

    "A fish hangs from a spring scale supported from the roof of an elevator. If the elevator has an upward acceleration of 1.2m/s^2 and the scale reads 200N, under what circumstances will the scale read 150N? What will the scale read

  3. physics

    In Figure (a), a block of mass m lies on a horizontal frictionless surface and is attached to one end of a horizontal spring (spring constant k) whose other end is fixed. The block is initially at rest at the position where the

  4. Physics

    A small 0.13 g bug stands at one end of a thin uniform bar that is initially at rest on a smooth horizontal table. The other end of the bar pivots about a nail driven into the table and can rotate freely, without friction. The bar

  1. physics

    A fish hangs from a spring scale supported from the roof of an elevator. a) if the elevator has an upward acceleration of 1.2 m/s^2 and the scale reads 200 N, what is the true force of gravity on the fish? b) under what

  2. math

    if two polygons are similar,how can you find the scale factor from one polygon to the other?show specific examples.describe how you find the scale factor from the smaller figure to the enlarged figure.then,describe how you find

  3. Physics

    A solid bar of length L = 1.32 m has a mass m1 = 0.751 kg. The bar is fastened by a pivot at one end to a wall which is at an angle θ = 35.0 ° with respect to the horizontal. (in other words, the angle between the wall and the

  4. Math

    The weight of an object exerts on a scale varies directly with the mass of an object. If a bowling ball has a mass of 6 kg, the scale reads 54. If another object has a mass of 8kg, what would the scale read?

  1. physics

    A compound metal bar has 4 kg of copper making up the first third of the bar, while the remainder is made of 12 kg of lead. The bar is 3 meters in length. In addition, a mass of 2 kg is hung 1m from the left end of the bar, and a

  2. math

    "Just look at the graph," the player's agent said. "Phil's hits have doubled since last year. We are looking for a large raise and a long contract." Look at the graph. Graph: i.imgur. com/wY0gqtQ.png How can you redraw this graph

  3. math HELP SOS

    If two polygons are similar,how can you find the scale factor from one polygon to the other?Show specific examples.Describe how you find the scale factor from the smaller figure to the enlarged figure.Then,describe how you find

  4. physics

    A uniform bar of length 12 m and mass 3 kg is attached to a wall with a hinge that exerts a horizontal force Hx and a vertiscal force Hy on the bar. The bar is held by a cord that makes a 90 degree angle with respect to bar and 43

You can view more similar questions or ask a new question.