4.
Given : P = 200 N , W = 450 N
Solution:
Torque for position (a)
T = Tp + Tw
= (200 N)(0.226 m) + (450 N)(0.088 m)
= 84.8 N-m
Torque for position (b)
T = Tp + Tw
= (200 N)(0.347 m) + (450 N)(0.184 m)
= 152.2 N-m
Difference in torques between position (a) and position (b) is :
152.2 - 84.8 = 67.4 N-m
Lifting position (b) causes the back muscle to work harder because in this position the torque is 152.2 N-m which is 67.4 N-m more than that in the position (a)
The figure below shows the same individual lifting a load (P) of 200 N using two...