Engineering Answers

An endless belt 4 m long passes over a pulley of 300 mm diameter making 80 rev/minute. The pulley accelerates to 240 rev/minute in 40 seconds. If there is no belt slip, calculate:

7.1 the angular acceleration of the pulley and the linear acceleration of the belt.

7.2 the number of revolutions made by the pulley during its acceleration.

7.3 the number of times a point on the belt will pass over the pulley in 12 seconds.

Also clearly show the values of the following:

ω1

ω2

α

a

θ

ω2

θ

s

times

A 320 mm diameter-grinding wheel must be driven at a peripheral grinding speed of 1200 meters/min. It takes 62 seconds to reach this speed from rest, runs at this speed for the following two and a half minutes and then begins to decelerate uniformly, coming to rest after a further 10 seconds. Draw a neat angular velocity/time graph and use it to determine how many revolutions the wheel made since starting from rest.

Also clearly show what the following values are

v

ω

θ1

θ2

θ3

θtotal