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Snezhnost [94]
2 years ago
14

The lubrication of bone joints is a subject of ongoing medical research. Two bones connected at a joint do not touch. The bones

are covered in articular cartilage, and are surrounded by lubricating synovial fluid. Rheumatoid arthritis results in overproduction of synovial fluid, swollen joints, and difficult and painful movement. Other joint disorders degrade the synovial fluid, directly increasing the friction between the bones, resulting in painful motion.
Part A



To measure the effective coefficient of friction in a bone joint, a healthy joint (and its immediate surroundings) can be removed from a fresh cadaver. The joint is inverted, and a weight is used to apply a downward force
Physics
1 answer:
maks197457 [2]2 years ago
5 0

The question is incomplete. The complete question is :

To measure the effective coefficient of friction in a bone joint, a healthy joint (and its immediate surroundings) can be removed from a fresh cadaver. The joint is inverted, and a weight is used to apply a downward force F⃗ d on the head of the femur into the hip socket. Then, a horizontal force F⃗ h is applied and increased in magnitude until the femur head rotates clockwise in the socket. The joint is mounted in such a way that F⃗ h will cause clockwise rotation, not straight-line motion to the right. The friction force will point in a direction to oppose this rotation.

Draw vectors indicating the normal force n⃗  (magnitude and direction) and the frictional force f⃗ f (direction only) acting on the femur head at point A.

Assume that the weight of the femur is negligible compared to the applied downward force.

Draw the vectors starting at the black dot. The location, orientation and relative length of the vectors will be graded

Solution :

The normal force represented by N is equal to the downward force, $F_d$ which is equal in magnitude but it is opposite in direction.

Also the frictional force acts always to oppose the motion because the bone starts moving in a clockwise direction. The frictional force that will be applied to the right direction so that the movement or the rotation at A is opposed.  

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Which of the following is a scalar quantity?
aleksandrvk [35]

Answer:

time is a scalar quantity.

8 0
3 years ago
An FM radio station broadcasts at 9.23 × 107 Hz. Given that the radio waves travel at 3.00 × 108 m/s, what is the wavelength of
STALIN [3.7K]

Answer:

3.2m

Explanation:

Given parameters:

Frequency of the FM radio = 9.23 x 10⁷Hz

Velocity of the waves = 3  x 10⁸m/s

Unknown:

Wavelength of the wave = ?

Solution:

To solve for the wavelength of the wave, we need the velocity equation;

       Velocity = frequency x wavelength.

Radio waves are all electromagnetic radiations produced by both electrical and magnetic fields perpendicularly oriented to one another.

 Since the unknown is wavelength, we solve for it:

       

    3  x 10⁸  = 9.23 x 10⁷ x wavelength

          wavelength = \frac{ 3 x 10^{8} }{9.23 x  10^{7} }

        wavelength = 3.2m

7 0
3 years ago
Jason is taking a physical exam and has to do push ups for sixty seconds. He does 30 pushups in the sixty seconds. Each push up
Alexandra [31]

Answer: 2 seconds is the unit rate.

Explanation:

We know that Jason does 30 pushups in 60 seconds at a constant rate, and we know that each push up takes 2 seconds.

then, we can write this as 30 pushups/60 seconds = (1/2) pushups per second.

Here, two seconds represents the time needed to do one pushup, is the unit rate (this means that we need 2 seconds to have a unit "one pushup")

8 0
3 years ago
A machine exerts a 100 N force to the right over a 5.00 meter length in 4.00 seconds. Calculate the power output of this machine
bixtya [17]

125 W is the power output of this machine.

Answer:

Explanation:

Power is defined as the amount of work done on the system to move that system from its original state within the given time interval. So it can be determined by the ratio of work done with time interval. As work done is the measure of force required to move a system to a certain distance. Work done is calculated as product of force with displacement.

So in the present case, the force is given as 100 N, the displacement is given as 5 m and the time is given as 4 s, then power is

Power = \frac{Work done}{Time}

As Work done = Force acting on the machine × Displacement

So Power = \frac{(Force * Displacement)}{Time}

Power = \frac{(100*5)}{4}=125 W

So, 125 W is the power output of this machine.

6 0
2 years ago
Lonnie pitches a baseball of mass 0.500 kg. The ball arrives at home plate with a speed of 35.0 m/s and is batted straight back
Andreyy89

Answer:

Explanation:

The impulse equation is

Δp = FΔt, where Δp = final momentum - initial momentum, F is the Force exerted on an object, and Δt is the change in time. In this equation,the entire right side defines the impulse. In other words, FΔt is the impulse; thus the change in momentum an object experiences is due to its change in impulse and is directly proportional to it.

Therefore, once we find the change in momentum, that is the impulse the object experiences. Δp = final momentum - initial momentum, where

p = mv and p is momentum.

p_f=(.500)(50.0) so

p_f=25.0 and

p_i=(.500)(35.0) so

p_i=17.5; therefore,

Δp = 25.0 - 17.5 = 7.5\frac{kg*m}{s} which is the unit for momentum

7 0
3 years ago
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