28 Questions
What is the force that controls all motion in the world?
Muscular force
What are the four fundamental forces recognized by physicists?
Gravitational, electrical, weak nuclear, and strong nuclear forces
What is the medical effect of gravitational force on the body?
Formation of varicose veins in the legs
What is the force that holds the nucleus together?
Strong nuclear force
What is the condition of equilibrium in statics?
The sum of the forces in any direction is zero
What is the formula for torque?
τ = F.L
What is the classification of levers based on?
The position of the fulcrum, effort, and load
What is the type of force that is involved in both statics and dynamics?
Frictional force
What is the condition for rotational equilibrium?
The sum of the torques about any axis is zero
What is the type of force that causes the blood to circulate and the lungs to take in air and other essential functions?
Muscular force
What is the force that resists the motion between two surfaces in contact?
Frictional force
What is the coefficient of static friction used to find?
Max. resistance force on an object before it starts to move
What is the force that supplies the effort in a lever system?
Muscle force
What is the type of friction that occurs when an object is stationary and on the verge of moving?
Static friction
What is the formula for force in terms of mass and velocity?
F = m × Δv
What is the formula to calculate the force in a lever system?
F = MW
What is one of the effects of acceleration on the human body?
An apparent increase or decrease in body weight
What is the purpose of a centrifuge in a laboratory?
To separate particles of different densities
What is the purpose of the synovial fluid in the joint?
To lubricate the joint
What is the condition when the coefficient of friction is less than 0.15?
The foot slips forward
What is the unit of measurement for hematocrit?
Percent
What is one of the factors that affects hematocrit?
Speed of centrifuge
What is the formula to calculate the horizontal force component of the heel?
Fh = 0.15W
What is the type of lever system where the load is between the fulcrum and the force?
Second class lever
What is the medical use of terminal velocity?
To diagnose blood diseases
What is the formula to calculate the force in one-dimensional motion?
F = ma
What happens to the sedimentation velocity of red blood cells in hemolytic jaundice?
It decreases
What is the purpose of centrifugation in diagnosing blood diseases?
To separate red blood cells from other components
Study Notes
Forces in the Body
- There are four fundamental forces in the body: gravitational, electrical, nuclear (strong and weak), and frictional force.
-
Gravitational Force:
- Attracts objects with mass towards each other
- Responsible for our weight
- Causes varicose veins in the legs due to the force of gravity on blood flow
-
Electrical Force:
- Responsible for muscle contraction and blood circulation
- Cells in the body have an electrical potential difference across the cell membrane
- Attracts opposite electrical charges
Levers in the Body
- Bones and muscles in the body act as levers
- Levers are classified into three classes: first, second, and third
-
First Class Lever:
- Fulcrum is between the effort and load
- Examples: joint between the skull and atlas vertebrae, spine
-
Second Class Lever:
- Load is between the fulcrum and effort
- Examples: Achilles tendon, pushing or pulling across the heel of the foot
-
Third Class Lever:
- Effort is between the fulcrum and load
- Examples: elbow joint, biceps muscle
Frictional Force
- A force that resists motion between two surfaces in contact
- Depends on the nature of the surface and is independent of the area of the surface
-
Static Friction:
- The effective force between surfaces that are at rest with respect to each other
- Coefficient of static friction (μs) is used to find the maximum resistance force on an object before it starts to move
-
Kinetic (Sliding) Friction:
- The effective force between surfaces that are in relative motion
- Coefficient of kinetic friction (μk) is used to calculate the force
- Friction in the body: walking, where frictional force prevents the foot from slipping forward or backward
Dynamics
- The force on the body under constant acceleration or deceleration of one-dimensional motion
- Newton's Second Law: force equal to mass times acceleration (F = ma)
-
Effects of Acceleration:
- Apparent increase or decrease in body weight
- Changes in internal hydrostatic pressure
- Distortion of elastic tissues in the body
- Pooling of blood in various regions of the body depending on the direction of acceleration
Centrifugation and Hematocrit
- Centrifugation: a laboratory test for diagnosing related blood diseases by separating particles in a liquid
- Hematocrit (Packed Cell Volume, PCV): the percentage of red blood cells in the blood
- Depends on the radius of the centrifuge, speed, and duration
- Medical use of terminal velocity: in diseases such as rheumatic fever, rheumatic heart disease, and gout, RBCs clump together, increasing sedimentation velocity, while in diseases such as hemolytic jaundice and sickle cell anemia, RBCs change or break, decreasing sedimentation velocity
Learn about the four fundamental forces in the human body, including gravitational, electrical, nuclear, and frictional forces. Understand how they impact our bodily functions and overall health.
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