## Power Units

What are the base SI units for power?

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__**Hint**

**Hint**

Power is the time rate of doing work. The unit for power is a watt (W).

Power is the time rate of doing work. The unit for power is a watt (W), which is one joule per second.

$$$1\:W=1\:\frac{J}{s}$$$

Joule (J) is a unit of work, which is the product of a unit force (one newton) acting through a unit distance (one meter).

$$$1\:J=1\:N\cdot m$$$

A newton is a unit of force, which is described in the following SI base units:

$$$\frac{m\cdot kg}{s^{2}}$$$

Combining all units together:

$$$W=\frac{J}{s}=\frac{N\cdot m}{s}=\frac{m^2\cdot kg}{s^{3}}$$$

(A familiar unit for power in English units is horsepower (hp), where
$$1\:hp=550\:\frac{ft\cdot lbf}{s}$$
)

$$$\frac{m^2\cdot kg}{s^{3}}$$$