The bones of the forearm (radius and ulna) are hinged to the humerus at the elbow. the biceps muscle connects to the bones of the forearm about 2.152.15 cm beyond the joint. assume the forearm has a mass of 2.452.45 kg and a length of 0.4650.465 m. when the humerus and the biceps are nearly vertical and the forearm is horizontal, if a person wishes to hold an object of mass 6.556.55 kg so that her forearm remains motionless, what is the force exerted by the biceps muscle?

 = 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

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

a skateboard rolling across the street - apex