Biomechanics Questions
Question 1. Definition of key concepts
Energy refers to the state of the matter that makes or has the potential to change things. It is also a state characterizing a system or a body and is used to change that system or body. Mechanical energy is of most interest in biomechanics and is classified into kinetic and Gravitational potential. The body possesses kinetic energy due to the motion. Kinetic energy is further classified based on the type of motion as linear kinetic and angular kinetic energy. Potential energy is the energy possessed by a stationary body with the potential to change. Potential energy is also classified into gravitational potential and strain potential. An object has gravitational potential energy due to its position relative to the earth’s surface (Flanagan, 2019). For instance, an object raised to some height has the potential energy to fall to the ground due to gravitational pull. The factors in play in calculating gravitational potential energy include the mass, height, and gravitational acceleration. However, an object on the ground does not possess this energy due to zero height. Strain potential energy exists in a stretched elastic objective such as rubber bands.
- 2: Energy needed to raise a 10kg of mass 0.5
Gravitation potential energy for raising an object
EGP = magh
Where EGP = gravitational potential energy
M = mass in kg = 10 kg
ag = gravitational acceleration = 10 N/Kg
h = Height in meters = 0.5 m
EGP = 10*10*0.5
= 50J
The raised 10kg object has a gravitational potential energy of 50J
Q3. Energy is required to lower a 5kg mass 0.1 m.
EGP = magh
Where EGP = gravitational potential energy
M = mass in kg = 5kg
ag = gravitational acceleration = 10 N/Kg
h = Height in meters = 0.1 m
EGP = 5*10*0.1
= 5J
Q4. The first law of thermodynamics
The equation for the center of mass is stated as:
W = ∆E – Q
Where W = work done on a body
∆E = Energy change
Q = Energy lost to environment as heat
A narrow range of possibilities is considered in the COM equation. The first law of thermodynamics offers more complete and additional information. As noted earlier, an object raised above the surface possesses a given amount of potential and kinetic energy. Typically, kinetic energy is transformed into potential energy, and the height reached is a function of kinetic energy at takeoff. The first law of thermodynamics states energy is neither created nor destroyed, but is instead transformed into different types of energy (Flanagan, 2019). In other words, it is impossible to get something from nothing. For a raised and lowered object, the energy is transformed from kinetic to potential energy as others are changed to the heat released to the environment.
Q5. Difference between efficiency and economy
Efficiency is the ratio of energy is the ratio of expended energy to metabolic energy. It is the amount of work performed by expended energy, energy used to perform the work. Typically, system efficiency is less than 100%, as some energy is lost as heat. Economy refers to the amount of energy needed to perform a specific amount of work (Flanagan, 2019). Using a lower amount of energy for the same amount of work is termed as more economical.
Reference
Flanagan, S.P. (2019). Biomechanics: A Case-Based Approach (2ndEd).Burlington, MA: Jones and Bartlett Learning.