The biceps muscle connects to the bones of the forearm about 2.15 cm beyond the joint. Assume the forearm has a mass of 2.25 kg and a length of 0.425 m.

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 2.15 cm beyond the joint. Assume the forearm has a mass of 2.25 kg and a length of 0.425 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 4.55 kg so that her forearm remains motionless, what is the force exerted by the biceps muscle?

Solutions

Expert Solution

Taking moment about pivot point,

(F x 0.0215) = (2.25 x 9.8 x 0.425/2) + (4.55 x 9.8 x 0.425)

F x 0.0215 = 23.64

Force, F = 1099.37 N

genius_generous answered 2 years ago

Next > < Previous

Related Solutions

A pendulum has a length 1 m and a mass 1 kg. Assume Earth free fall...

A pendulum has a length 1 m and a mass 1 kg. Assume Earth free fall acceleration equal to 10 m/s^2. When the pendulum oscillates, the maximal deflection angle is +/-1 degree. 1.Suppose the pendulum started losing energy at the rate 1% per period. As a result, the energy of the pendulum drops according to E(t)= E(t=0)*exp(-z*t). Let’s call z damping constant, it has units 1/sec. a) Find Z b) Sketch E(t) for the time span of a few hundred...

A pendulum has a length 1 m and a mass 1 kg. Assume Earth free fall...

A pendulum has a length 1 m and a mass 1 kg. Assume Earth free fall acceleration equal to 10 m/s^2. When the pendulum oscillates, the maximal deflection angle is +/- 1 degree. a) If the maximal deflection angle doubles, what would be the new period? b) If the pendulum mass goes up 100 times, what would be the new period? c) If the length goes up 100 times, what would be the period? d) If the pendulum moves to...

A pendulum has a length 1 m and a mass 1 kg. Assume Earth free fall...

A pendulum has a length 1 m and a mass 1 kg. Assume Earth free fall acceleration equal to 10 m/s^2. When the pendulum oscillates, the maximal deflection angle is +/- 1 degree. a) How long will it take before the energy drops to half of the initial value at t=0? b) How long will it take before the max deflection angle drops to half of the initial value at t=0? c) If the damping was produced by a force...

A girl of mass, m = 40 kg has osteoporosis which weakens her bones. From a...

A girl of mass, m = 40 kg has osteoporosis which weakens her bones. From a kneeling position, she topples forward onto her elbows with her upper arms extended vertically downwards on impact with the ground. In falling forward, her centre of mass lowers by a height, h = 50 cm and she absorbs all of her kinetic energy from her fall into her two humerus bones (one bone in each upper arm). Determine an equation for the stress in...

A simple pendulum has a mass of 0.550 kg and a length of 2.00 m. It...

A simple pendulum has a mass of 0.550 kg and a length of 2.00 m. It is displaced through an angle of 11.0

A simple pendulum has a mass of 0.650 kg and a length of 7.00 m. It...

A simple pendulum has a mass of 0.650 kg and a length of 7.00 m. It is displaced through an angle of 14.0° and then released. Using the analysis model of a particle in simple harmonic motion, calculate the following. (Give your answer to the thousandths place.) (a) What is the maximum speed of the bob? (b) What is the maximum angular acceleration of the bob? (rad/s2) (c) What is the maximum restoring force of the bob? (d) Solve parts...

A uniform rod of mass 2.20 kg and length 2.00 m is capable ofrotating about...

A uniform rod of mass 2.20 kg and length 2.00 m is capable of rotating about an axis passing through its center and perpendicular to its length. A mass m1 = 4.90 kg is attached to one end and a second mass m2 = 2.60 kg is attached to the other end of the rod. Treat the two masses as point particles. At the origina of an xy-coordinate plane a rod of length labeled l rotates around it's midpoint. Attached to...

A bicycle wheel has a diameter of 63.0 cm and a mass of 1.74 kg. Assume...

A bicycle wheel has a diameter of 63.0 cm and a mass of 1.74 kg. Assume that the wheel is a hoop with all of the mass concentrated on the outside radius. The bicycle is placed on a stationary stand and a resistive force of 117 N is applied tangent to the rim of the tire. (a) What force must be applied by a chain passing over a 8.99-cm-diameter sprocket in order to give the wheel an acceleration of 4.49...

A spring has an unstretched length of 0.31 m. A block with mass 0.23 kg is...

A spring has an unstretched length of 0.31 m. A block with mass 0.23 kg is hung at rest from the spring, and the spring becomes 0.37 m long. Next the spring is stretched to a length of 0.43 m and the block is released from rest. Air resistance is negligible. How long does it take for the block to return to where it was released? Next the block is again positioned at rest, hanging from the spring (0.37 m...

QUESTION 14 A chimney (length 18 m, mass 980 kg] cracks at the base and topples. Assume:...

QUESTION 14 A chimney (length 18 m, mass 980 kg] cracks at the base and topples. Assume: - the chimney behaves like a thin rod, and does not break apart as it falls. - only gravity (no friction) acts on the chimney as it falls. - the bottom of the chimney pivots, but does not move. Find the linear speed of the very top of the chimney, in m/s, just as it hits the ground. QUESTION 15 A 23 kg cart...

Subjects