A door of width 0750 m requires a minimum torque of 128 Nm t

A door of width 0.750 m requires a minimum torque of 12.8 N·m to open. What is the minimum force necessary to open the door using the door knob that is located 0.680 m from the edge of the door with the hinges?

A door of width 0.750 m requires a minimum torque of 12.8 N·m to open.

What is the minimum force necessary to open the door using the door knob that is located 0.310 m from the edge of the door with the hinges?

Solution

Minimum torque T = 12.8 Nm

Location of the knob from edge of the door r = 0.68 m

the minimum force necessary to open the door using the door knob that is located 0.680 m from the edge of the door with the hinges F = T/ r

                                 = 12.8 / 0.68

                                 = 18.82 N

(b).

Minimum torque T = 12.8 Nm

Location of the knob from edge of the door r = 0.31 m

the minimum force necessary to open the door using the door knob that is located 0.310 m from the edge of the door with the hinges F = T/ r

                                 = 12.8 / 0.31

                                 = 41.29 N