# How much work does it take to raise a 4 kg  weight 9 m ?

Jan 13, 2016

Work = force $\cdot$ distance

#### Explanation:

The force required to lift a 4 kg mass is it's weight, ${F}_{g}$, where

${F}_{g} = m \cdot g$, and $g$ is the gravitational field strength, 9.8 N/kg

so

$W = F \cdot d$
$W = m \cdot g \cdot d$
$W = 4 k g \cdot 9.8 \frac{N}{k g} \cdot 9 m$

Note that some texts use 9.81 for $g$, and others suggest rounding up to 10 to simplify for purposes of focusing on conceptual principles, rather than calculation.