What is the relationship between the motor neurons and muscle fibers?
What is the relationship between the motor neurons and muscle fibers?
Each lower motor neuron innervates muscle fibers within a single muscle, and all the motor neurons innervating a single muscle (called the motor neuron pool for that muscle) are grouped together into rod-shaped clusters that run parallel to the long axis of the cord for one or more spinal cord segments (Figure 16.2).
What is the relationship between muscle fiber arrangement and the force that a muscle can produce?
Muscle fibers may run parallel or obliquely to the axis of pull, the latter resulting in fibers inserting into the tendon at an angle (usually between 0° and 30°); this is called the “angle of pennation.” These two arrangements are referred to as parallel and pennate and have a significant effect on the force developed …
What is the relationship between size of motor unit and amount of tension produced?
The smaller motor units in a muscle have motor neurons that are more excitable. Initial activation of these smaller motor units results in a relatively small degree of tension generated in a muscle. As more strength is needed, larger motor units are enlisted to generate more tension.
What is the relation between maximal force development and the speed of shortening concentric and lengthening eccentric contractions?
What is the relation between maximal force development and the speed of shortening (concentric) and lengthening (eccentric) contractions? Shortening (concentric) contractions, maximal force development decreases progressively at higher speeds.
Is length a force?
The measurement of length can be done by measuring instruments, such as a measuring tape, yardstick, ruler, etc. The calculation of Vector Sum of forces can be carried out using (m * a). Clearly, Length is NOT a FORCE.
What are the 10 types of forces?
Types of Forces
| Contact Forces | Action-at-a-Distance Forces |
|---|---|
| Frictional Force | Gravitational Force |
| Tension Force | Electrical Force |
| Normal Force | Magnetic Force |
| Air Resistance Force |
What is the relationship between muscle length and force?
The force -length relationship indicates that muscles generate the greatest force when at their resting (ideal) length, and the least amount of force when shortened or stretched relative to the resting length.
Is friction A physics?
Friction is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
How is friction calculated?
Friction is a resistive force that prevents two objects from sliding freely against each other. The coefficient of friction (fr) is a number that is the ratio of the resistive force of friction (Fr) divided by the normal or perpendicular force (N) pushing the objects together.
Which type of friction is the weakest?
Rolling friction is the weakest kind of friction. It is the force that resists the motion of an object rolling across a surface.
What are the two advantage and disadvantage of friction?
Friction produces unnecessary heat leading to the wastage of energy. The force of friction acts in the opposite direction of motion, so friction slows down the motion of moving objects. Forest fires are caused due to the friction between tree branches.
What are the two disadvantages of friction?
Disadvantages of friction:
- Friction produces a lot of heat in various parts of the machinery and this leads to wastage of energy as heat.
- Opposes motion, hence more energy is needed to overcome friction.
- Noise production in machines is irritating as well as leads to energy loss.
How is friction not useful in everyday life?
Friction can also be unhelpful. If you do not lubricate your bike regularly with oil, the friction in the chain and axles increases. Your bike will be noisy and difficult to pedal. When there is a lot of friction between moving parts, energy is transferred to the surroundings, causing heating.
Is friction good or bad?
Friction can slow things down and stop stationary things from moving. In a frictionless world, more objects would be sliding about, clothes and shoes would be difficult to keep on and it would be very difficult for people or cars to get moving or change direction.
Do we need to reduce friction?
Friction is a necessary evil which causes a lot of wear and tear in machine parts that move against each other. It erodes the surfaces and destroys their symmetries. Hence, in such cases it is desirable to reduce friction. Friction is reduced by lubricating surfaces to decrease the friction.
How do we use friction in everyday life?
10 examples of friction in our daily life
- Driving of a a vehicle on a surface.
- Applying brakes to stop a moving vehicle.
- Skating.
- Walking on the road.
- Writing on notebook/ blackboard.
- Flying of aeroplanes.
- Drilling a nail into wall.
- Sliding on a garden slide.
What is bad about friction?
Friction manifests as heat energy generally and sometimes as noise. When objects are moving against each other, there is a generation of kinetic energy. Friction causes this kinetic energy to change into thermal energy. The biggest disadvantage of friction is wear and tear that happens as a result of friction.
What is an example of unwanted friction?
Friction is unwanted in any situation in which free and continuous motion of mechanical parts is necessary. Some examples include the moving parts inside of an engine, door hinges and water slides. Frictional forces oppose moving objects.
How can you reduce friction in real life?
Methods of reducing friction
- Make surfaces smooth by grinding.
- Lubrication.
- Streamlined body.
- Reduce pressure or weight on the object.
- Reduce contact between surfaces by electrostatic magnetic levitation etc.
- Use rolling friction instead of sliding friction.
- Use fluid friction instead of the dry friction.
Can water reduce friction?
Water can either increase or decrease the friction between two surfaces. Water reduces the friction between rubber tires and road pavements. Water can also increase the friction between two sheets of glass.
What are 4 ways to reduce friction?
Methods for decreasing friction:
- Make the surfaces smoother. Rough surfaces produce more friction and smooth surfaces reduce friction.
- Lubrication is another way to make a surface smoother.
- Make the object more streamlined.
- Reduce the forces acting on the surfaces.
- Reduce the contact between the surfaces.
What 4 things can Friction do?
Friction is the force that opposes motion between any surfaces that are in contact. There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Fluid friction occurs in liquids and gases.
Why can’t we walk without friction?
Without friction, we wouldn’t be able to walk, run, or drive our cars. On the other hand, friction can also reduce energy efficiency such as the air friction that fights against the motion of vehicles. Consider the good first. In order to move forward, we need to push back on something.
Where is friction not useful?
Friction is sometimes unhelpful. For example, if you don’t lubricate your bike regularly with oil, the friction in the chain and axles increases. Your bike will be noisy and difficult to pedal. When there is a lot of friction between moving parts, energy is lost to the surroundings as heat.