13 - Length of Belt Connecting Two Pulleys

Two flat belt pulleys have a center to center distance of 137 cm, and diameters of 72 cm and 36 cm, respectively. Neglecting the sagging of belt.

  1. Compute the length of belt if both pulleys will rotate in the same direction.
    A.   464.5 cm
    B.   553.1 cm
    C.   446.0 cm
    D.   535.4 cm



  2. Compute the length of belt if the belt will be cross-connected to make the pulleys rotate in opposite directions.
    A.   654.1 cm
    B.   465.2 cm
    C.   564.2 cm
    D.   645.1 cm



  3. Determine the distance of the point from the center of the bigger pulley where the belt will cross when cross-connected.
    A.   91.3 cm
    B.   100.4 cm
    C.   89.4 cm
    D.   98.7cm

Problem 523 | Friction

Problem 523
A force of 400 lb is applied to the pulley shown in Fig. P-523. The pulley is prevented from rotating by a force P applied to the end of the brake lever. If the coefficient of friction at the brake surface is 0.20, determine the value of P.

Lever and pulley system to form a brake


Problem 352 | Equilibrium of Non-Concurrent Force System

Problem 352
A pulley 4 ft in diameter and supporting a load 200 lb is mounted at B on a horizontal beam as shown in Fig. P-352. The beam is supported by a hinge at A and rollers at C. Neglecting the weight of the beam, determine the reactions at A and C.

Pulley mounted at the midspan of simple beam


Problem 340 - 341 | Equilibrium of Parallel Force System

Problem 340
For the system of pulleys shown in Fig. P-340, determine the ratio of W to P to maintain equilibrium. Neglect axle friction and the weights of the pulleys.

System of Five Pulleys


Problem 339 | Equilibrium of Parallel Force System

Problem 339
The differential chain hoist shown in Fig. P-339 consists of two concentric pulleys rigidly fastened together. The pulleys form two sprockets for an endless chain looped over them in two loops. In one loop is mounted a movable pulley supporting a load W. Neglecting friction, determine the maximum load W that can just be raised by a pull P supplied as shown.

Differential Chain Hoist


Problem 319 | Equilibrium of Concurrent Force System

Problem 319
Cords are loop around a small spacer separating two cylinders each weighing 400 lb and pass, as shown in Fig. P-319 over a frictionless pulleys to weights of 200 lb and 400 lb . Determine the angle θ and the normal pressure N between the cylinders and the smooth horizontal surface.

Cords loop around the spacer of cyliders


247 - Resultant of couples in a 3-step pulley

Problem 247
The three-step pulley shown in Fig. P-247 is subjected to the given couples. Compute the value of the resultant couple. Also determine the forces acting at the rim of the middle pulley that are required to balance the given system.

Couples on three-step pulley


Solution to Problem 505 | Flexure Formula

Problem 505
A high strength steel band saw, 20 mm wide by 0.80 mm thick, runs over pulleys 600 mm in diameter. What maximum flexural stress is developed? What minimum diameter pulleys can be used without exceeding a flexural stress of 400 MPa? Assume E = 200 GPa.

Solution to Problem 118 Shear Stress

Problem 118
A 200-mm-diameter pulley is prevented from rotating relative to 60-mm-diameter shaft by a 70-mm-long key, as shown in Fig. P-118. If a torque T = 2.2 kN·m is applied to the shaft, determine the width b if the allowable shearing stress in the key is 60 MPa.

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