OT 322 Chapter 2: Study Guide

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lilacbear269

15 Mar 2018

School

Quinnipiac University

Department

Occupational Therapy

Course

OT 322

Professor

Dee

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Document Summary

Examining forces: equilibrium: opposing forces are balanced, displacement: motion of a body when force is applied, force: a push or pull that produces displacement. Forces that affect body motion: gravity, muscles, other externally applied resistances, friction: resistance to movement between 2 objects in contact with one another. Newton"s third law: action- reaction: for every action force there is an equal and opposite reaction force, every time you hit the ground, the ground is hitting back with the same amount of force. Composition of forces: multiple forces on a body can be combined into a resultant vector, resultant force = simplest combination of force that produces the same effect as all forces acting on body, must be parallel or co-planar. Go through examples that we did in class. Mechanical principle ii: kinetics (applying forces as simple lever systems) Mechanical advantage: ration between the length of the force arm (ima) and the length of the resistance arm (ema)

Related Questions

Good Vibes: Introduction to Oscillations

The conditions that lead to simple harmonic motion are as follows:

There must be a position of stable equilibrium.

There must be a restoring force acting on the oscillating object. The direction of this force must always point toward the equilibrium, and its magnitude must be directly proportional to the magnitude of the object's displacement from its equilibrium position. Mathematically, the restoring force F⃗ is given by ⃗, where is the displacement from equilibrium and k is a constant that depends on the properties of the oscillating system.

The resistive forces in the system must be reasonably small.

Consider a block of mass m attached to a spring with force constant k, as shown in the figure(Figure 1) . The spring can be either stretched or compressed. The block slides on a frictionless horizontal surface, as shown. When the spring is relaxed, the block is located at x=0. If the block is pulled to the right a distance A and then released, A will be the amplitude of the resulting oscillations.

Assume that the mechanical energy of the block-spring system remains unchanged in the subsequent motion of the block.

Part A

After the block is released from x=A, it will

(a) remain at rest

(b) move to the left until it reaches equilibrium and stop there.

(d) move to the left until it reaches x=−A and then begin to move to the right.

The time it takes the block to complete one cycle is called the period. Usually, the period is denoted T and is measured in seconds.

The frequency, denoted f, is the number of cycles that are completed per unit of time: f=1/T. In SI units, f is measured in inverse seconds, or hertz (Hz).

Part B

If the period is doubled, the frequency is

(a) unchanged

(b) doubled

Part C

An oscillating object takes 0.10 s to complete one cycle; that is, its period is 0.10 s. What is its frequency f?

Express your answer in hertz.

Part D

If the frequency is 40 Hz, what is the period T?

Express your answer in seconds.

The following questions refer to the figure (Figure 2) that graphically depicts the oscillations of the block on the spring.

Note that the vertical axis represents the x-coordinate of the oscillating object, and the horizontal axis represents time.

Part E

Which points on the x-axis are located at a distance A from the equilibrium position?

(a) R only

(b) Q only

Part F

Suppose that the period is T. Which of the following points on the t-axis are separated by the time interval T?

(a) K and L

(b) K and M

(d) L and N

(e) M and P

Now assume for the remaining Parts G - J, that the x coordinate of point R is 0.12 m and the t coordinate of point K is 0.0050 s.

Part G

What is the period T?

Express your answer in seconds.

Part H

How much time t does the block take to travel from the point of maximum displacement to the opposite point of maximum displacement?

Express your answer in seconds.

Part I

What distance d does the object cover during one period of oscillation?

Express your answer in meters.

Part J

What distance d does the object cover between the moments labeled K and N on the graph?

Express your answer in meters.

emeraldyak680

What is the difference between the study of kinematics and kinetics in regard to forces?

What three components that make up the musculoskeletal âsystemâ.

The musculoskeletal system is composed if many simple machines. There are 4 potential uses for these simple machines, list 2 of these uses.

Fill in the blank a _________ is used to alter the resulting direction of the applied force.

In the body what component acts as a lever and what acts as the axis?

When we think of a lever set up, what does FAR refer to?

Draw a basic F.A.R for each of the following and give an example of where in the body you may find each.

First class lever:

Second class lever:

Third class lever:

Which class of levers is designed best for speed and range of motion and which is best for strength?

What forces determine amount of torque in a system?

A. How much torque needs to be produced to move 60 kg (R) when the RA is 0.30 m and the FA is 0.1 meters?

b. What value could you change to decrease the torque needed to lift the SAME object.

c. Draw the F.A.R unit (say an arm lifting a bucket) label the elements and explain why what you changed in b would decrease torque needed.

12. a. What is the âcontractileâ unit of muscle called? ______________

b. what is the non-contractile element (series elastic element) in a muscle lever system?

13. in regards to âpowerâ which is more powerful, muscle fibers arranged in Parallel or bipennate muscles? ___________

Why?

14. When weight lifting with the goal of increasing strength, what physical characteristic of the muscle are you changing to bring about that increased strength? __________________

15. What is the branch of FDA that controls regulation of medical devices? ____________

16. Which of the following statements is false?

A device can be an instrument or an apparatus.

A device can be something used to diagnose a disease

A device can change the chemistry of your cells

A device can be something that delivers a drug to your body

17. Give one example of a..

Class I device

Class II device

Class III device

18. Which of the following is true regarding device classification?

Devices with the least risk to the patient are considered Class III

A class III device has a high risk potential to the patient

Class III devices are the easiest to get approved

Testing devices on humans is easy and follows no specific guidelines

19. Explain the difference between Harm and Risk.

20. What is a âsubstantial equivalentâ? Is it easier or harder to get approval for a Device that has an SE?

21. Which of the following would not be a priority when developing a medical device?

Cost

Ergonomics

Ease of sterilization

Material

None of the above

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OT 322 Chapter 2: Study Guide

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