26 Questions
What is the force of attraction between any two objects according to Newton's law?
Gravitational force
What is the unit of acceleration due to gravity?
m/sec²
What is the cause of our weight?
Attraction between the earth and our bodies
What is the medical effect of gravitational force on the human body?
Formation of varicose veins
What is the symbol used to represent the acceleration due to gravity?
g
What is the unit of mass?
kg
What happens to blood flow in the legs due to gravity?
Blood flow decreases with gravity
What is the effect of weightlessness on bone health?
Bones lose mineral content
What type of forces are involved in electrical charges?
Both attractive and repulsive forces
In which direction does blood flow in the legs in relation to gravity?
Against the direction of gravity
Why is the electrical force more complicated than gravity?
Electrical force involves both attractive and repulsive forces
What is the main cause of the forces produced by the muscles in our bodies?
Electrical charges attracting or repelling other electrical charges
What is the approximate ratio of the electrical force between an electron and a proton in a hydrogen atom compared to the gravitational force between them?
9301:1
Why can we consider our bodies as electrical machines?
Because they use electrical charges to function
What type of energy is generated by the muscle movement in our bodies?
Electrical energy
What is the relationship between the electrical force and the gravitational force between an electron and a proton in a hydrogen atom?
The electrical force is stronger than the gravitational force
What is the direction of the normal force N?
perpendicular to the surface
What is the purpose of the coefficient of friction μs?
to determine the maximum static friction
What is the result of exerting a force on an object before it starts to move?
there will be resistance to the motion
What is the relationship between the normal force and the force of friction?
the normal force and the force of friction are proportional
What is the purpose of considering the force of friction when moving an object?
to increase the force required to move the object
What is the definition of a fulcrum in a first-class lever?
The point where the weight and force are on opposite sides
What is an example of a first-class lever in the human body?
The joint between the skull and the atlas vertebrae of the spine
What is the role of the fulcrum in a first-class lever?
To balance the weight and force
In a first-class lever, where is the fulcrum located?
Between the effort and the load
What is the type of lever system where the fulcrum is located between the weight and force?
First-class lever
Study Notes
Forces in the Universe
- There are four fundamental forces in the universe: strong nuclear force, weaker nuclear force, gravitational force, and electrical force.
Gravitational Force
- Gravitational force is a force of attraction between any two objects (Newton's law).
- The force of attraction is equal to the product of the masses of the two objects and the acceleration due to gravity (F = mg).
- Acceleration due to gravity is 9.8 m/s² (or cm/s²).
- Mass is measured in grams (g) or kilograms (kg), and force is measured in Newtons (N) or dyne.
Effects of Gravitational Force on the Human Body
- Gravitational force causes the formation of varicose veins in the legs as venous blood travels against the force of gravity on its way to the heart.
- Gravitational force contributes to healthy bones, and weightlessness can lead to mineral loss and bone weakening.
Electrical Force
- Electrical force is more complicated than gravity, involving attractive and repulsive forces between static electrical charges.
- Electrical forces are responsible for the functioning of the human body's electrical machines (e.g., muscles).
- Electrical charges can attract or repel each other, producing forces that cause movement.
Levers and Fulcrums
- A first-class lever is an example of a machine that uses electrical forces to produce movement.
- In a first-class lever, the fulcrum is the point around which the force is applied, and the effort is applied on one side of the fulcrum, while the load is on the other side.
- An example of a first-class lever is the joint between the skull and the atlas vertebrae of the spine, where the spine acts as the fulcrum and the muscles lift the head.
Learn about the fundamental forces in the universe, focusing on gravitational force, its formula, and units of measurement.
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