A square threaded screw jack of mean diameter 25mm and pitch of 6mm is used to lift the load of 150 Newton .find the torque generated at the mean circumference if the coefficient of friction between the screw and nut is 0.02.

Answer 1

The torque generated can be calculated using the equation:

Torque = Frictional Force x Mean Circumference

First, let's calculate the frictional force.

Frictional Force = Coefficient of Friction x Normal Force

Normal Force = Load / (2 x π x (Mean Diameter / 2))

Normal Force = 150 N / (2 x π x (25 mm / 2))

Normal Force = 150 N / (2 x π x 12.5 mm)

Normal Force = 150 N / (78.54 mm)

Normal Force = 1.907 N

Frictional Force = 0.02 x 1.907 N

Frictional Force = 0.03814 N

Next, let's calculate the mean circumference.

Mean Circumference = π x Mean Diameter

Mean Circumference = π x 25 mm

Mean Circumference = 78.54 mm

Now we can calculate the torque.

Torque = 0.03814 N x 78.54 mm

Torque = 2.999 N·mm

The torque generated at the mean circumference is 2.999 N·mm.