Answer:
= 1647.92 N
Explanation:
Given:
length of the arm, r = 0.465 m
distance of forearm from elbow, r' = 2.15 cm = 0.0215 m
Mass of the forearm, M = 2.45 kg
Mass of the object, m = 6.55 kg
Let, the Force by bicep be, 
under the motionless condition, the net moment about elbow is zero
thus,
× 0.0215 - Mg × (0.465/2) - mg × (0.465) = 0
or
× 0.0215 - 2.45 × 9.8 × (0.465/2) - 6.55 × 9.8 × (0.465) = 0
or
× 0.0215 - 5.582 - 29.848 = 0
or
= 1647.92 N
hence, the force exerted by the elbow is 1647.92 N