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Speed reduction in a gear box is achieved using a worm and worm wheel. The worm wheel has 30 teeth and a pitch diameter of 210 mm. If the pressure angle of the worm is 20o, what is the axial pitch of the worm?
A planetary gear train is shown in the figure. Number of teeth on the sun gear A, planet gear B and fixed ring gear D are given by 30, 70 and 140 respectively. Module is taken as 5mm. Calculate the shaft angle for opposite hand of helix if helix angle of two gears are 20⁰ and 17⁰.
A gear train consist of spur gear as shown. Gear A receives 4kW of power at 750rpm through its shaft and rotates in CW direction. A gear train consist of spur gear as shown. Gear A receives 4kW of power at 750rpm through its shaft and rotates in CW direction. Calculate the torque on the gear C if number of teeth on gear A, B and C are 40, 70 and 30.
Which of the following is NOT true about Frictional force? A. Friction is the force which opposes the relative motion of two surfaces in contact. B. The force of friction that acts when a body is moving (sliding) on a surface is called sliding friction. C. Friction in machines wastes energy and also causes wear and tear. D. Rolling friction is much more than sliding friction, the use of ball bearings in a machine considerably reduces friction.
Consider the following statements: 1. According to Terzaghi, the average angle of wall friction may be taken equal to two-thirds of the respective angle of internal friction. 2. Wall friction increases the active earth Pressure and also decreases the passive earth resistance of the soil 3. Wall friction decreases the active earth pressure and increases the passive earth resistance of the soil. Which of the above statements is/are Correct?
Consider the following statements: 1. The kinetic friction is always less than the rolling friction. 2. The kinetic friction is always equal to the rolling friction. 3. The kinetic friction is always greater than the rolling friction. Which of the following statement is correct?
If worm helix angle is 30⁰, then worm should have at least ___ threads.
While discussing about friction, a teacher gave a number of examples to explain the concept. Some of the examples where friction is useful in our day-to-day life as quoted by the teacher are given below : A. We are able to write because of friction between the tip of the pen and the paper. B. We are able to walk because of friction between our feet and the ground. C. A ball thrown vertically upwards comes back to us due to friction. D. We are able to stop a moving vehicle by applying brakes because of friction. The correct examples were
Find the helix angle of the worm if the pitch of the worm gear is 12 mm and the pitch diameter is 50 mm.
A planetary gear train is shown in the figure. Number of teeth on the sun gear A, planet gear B and fixed ring gear D are given by 30, 70 and 140 respectively. Module is taken as 5mm. A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the gear ratio.