What formula relates work and power?
Force must act in the same direction as the object moves 14.1 Assessment Page 10 Question #2 What formula relates work and power? Power = Work / Time 14.1 Assessment Page 11 Question #3 A desk exerts an upward force to support a computer resting on it.
What is the relation between work and power?
Work is the energy needed to apply a force to move an object a particular distance, where force is parallel to the displacement. Power is the rate at which that work is done.
How do you calculate work and power?
Power equals work (J) divided by time (s). The SI unit for power is the watt (W), which equals 1 joule of work per second (J/s). Power may be measured in a unit called the horsepower.
What are the examples of zero work done?
5 examples of zero work
- If a block is moving on a smooth horizontal surface, no work is done.
- You are carrying two bags in your hands and not moving .
- A person holds a bundle of hay over his head for 30 minutes and gets tired.
- If you push a wall , but it does not move .
- You sit on a chair for hours .
What is meant by zero work done?
When force and displacement are perpendicular to each other, or when force or displacement is zero. Example: When we hold an object and walk, the force acts in a downward direction whereas displacement acts in the forward direction.
What is positive work Negative work and zero work?
Positive work done – The work done is said to be positive when force and displacement are in the same direction. Hence, work is positive. Zero work – the work done is said to be zero when force and displacement are perpendicular to each other.
Is work positive or negative?
If work is done on the system, its sign is positive. If work is done by the system, its sign is negative.
How do you know if a force is positive or negative?
Work can be either positive or negative: if the force has a component in the same direction as the displacement of the object, the force is doing positive work. If the force has a component in the direction opposite to the displacement, the force does negative work.
Can power be negative?
Yes. For example, let’s look at how we look at power. Power is the rate of change in the energy of a system, so if energy leaving the system is positive, then energy entering would mean that the power is negative. Generally, if something absorbs power, the power is positive.
What is the power of negative 1?
As the page explains, a negative exponent just means “the multiplicative inverse of the base raised to the positive opposite of the power”. So a^(-b) = 1/(a^b). The base, a, doesn’t change. Only its place in the expression changes.
What does negative power indicate?
A positive exponent tells us how many times to multiply a base number, and a negative exponent tells us how many times to divide a base number. We can rewrite negative exponents like x⁻ⁿ as 1 / xⁿ. For example, 2⁻⁴ = 1 / (2⁴) = 1/16.
Why is the power factor negative?
A negative power factor occurs when the device (which is normally the load) generates power, which then flows back towards the source. In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred.
What is the use of power factor?
Power factor is a measure of how effectively you are using electricity. Various types of power are at work to provide us with electrical energy. Here is what each one is doing. Working Power – the “true” or “real” power used in all electrical appliances to perform the work of heating, lighting, motion, etc.
What is electrical power factor?
Power factor refers to the ability of your electrical system to convert electric current into useful work such as heat, light, and mechanical motion. To use electrical power efficiently your system should draw mostly real power, measured in kilowatts (kW), from our system.
What is the power factor tariff?
demand meter is required. 6. Power factor tariff: The tariff in which power factor of the consumer’s load is taken into consideration is known as power factor tariff.In an a.c. system, power factor plays an important role. A low power factor increases the rating of station equipment and line losses.