Power (physics) - Wikipedia
In physics, power is the rate of doing work or transferring heat, the amount of energy transferred .. The similar relationship is obtained for rotating systems, where TA and ωA are the torque and angular velocity of the input and TB and ωB are. Below are a number of typical physical relationships exhibited graphically using standard X-Y coordinates (e.g., no logarithmic, power, trigonometric, or inverse. The units of power are watts, the units of energy are joules. A watt is one What is the relationship between power and energy and time?.
In solving work problems, one must always be aware of this definition - theta is the angle between the force and the displacement which it causes.
If the force is in the same direction as the displacement, then the angle is 0 degrees. If the force is in the opposite direction as the displacement, then the angle is degrees.
If the force is up and the displacement is to the right, then the angle is 90 degrees. This is summarized in the graphic below. Power Power is defined as the rate at which work is done upon an object. Like all rate quantities, power is a time-based quantity. Power is related to how fast a job is done. Two identical jobs or tasks can be done at different rates - one slowly or and one rapidly.
The work is the same in each case since they are identical jobs but the power is different. The equation for power shows the importance of time: Special attention should be taken so as not to confuse the unit Watt, abbreviated W, with the quantity work, also abbreviated by the letter W.
Combining the equations for power and work can lead to a second equation for power. A few of the problems in this set of problems will utilize this derived equation for power.
Torque - Wikipedia
Mechanical, Kinetic and Potential Energies There are two forms of mechanical energy - potential energy and kinetic energy. Potential energy is the stored energy of position. In this set of problems, we will be most concerned with the stored energy due to the vertical position of an object within Earth's gravitational field. Kinetic energy is defined as the energy possessed by an object due to its motion. An object must be moving to possess kinetic energy.
The amount of kinetic energy KE possessed by a moving object is dependent upon mass and speed. The total mechanical energy possessed by an object is the sum of its kinetic and potential energies. Work-Energy Connection There is a relationship between work and total mechanical energy.
The final amount of total mechanical energy TMEf possessed by the system is equivalent to the initial amount of energy TMEi plus the work done by these non-conservative forces Wnc. The mechanical energy possessed by a system is the sum of the kinetic energy and the potential energy. Positive work is done on a system when the force doing the work acts in the direction of the motion of the object.
Negative work is done when the force doing the work opposes the motion of the object. When a positive value for work is substituted into the work-energy equation above, the final amount of energy will be greater than the initial amount of energy; the system is said to have gained mechanical energy.
A person is also a machine that has a power rating. Some people are more power-full than others. That is, some people are capable of doing the same amount of work in less time or more work in the same amount of time.
Mechanics: Work, Energy and Power
A common physics lab involves quickly climbing a flight of stairs and using mass, height and time information to determine a student's personal power. Despite the diagonal motion along the staircase, it is often assumed that the horizontal motion is constant and all the force from the steps is used to elevate the student upward at a constant speed. Thus, the weight of the student is equal to the force that does the work on the student and the height of the staircase is the upward displacement.
Suppose that Ben Pumpiniron elevates his kg body up the 2.
If this were the case, then we could calculate Ben's power rating. It can be assumed that Ben must apply an Newton downward force upon the stairs to elevate his body.
By so doing, the stairs would push upward on Ben's body with just enough force to lift his body up the stairs. It can also be assumed that the angle between the force of the stairs on Ben and Ben's displacement is 0 degrees.Energy, Work and Power
With these two approximations, Ben's power rating could be determined as shown below. Ben's power rating is Watts. He is quite a horse. This is shown below. This new equation for power reveals that a powerful machine is both strong big force and fast big velocity. A powerful car engine is strong and fast. A powerful piece of farm equipment is strong and fast. A powerful weightlifter is strong and fast.
A powerful lineman on a football team is strong and fast. A machine that is strong enough to apply a big force to cause a displacement in a small mount of time i.