Question

what is a joule, which is a unit of work, equal to?
a newton times a meter
a newton divided by a second
a newton divided by a meter
a newton times a second

Explanation:

Work \(W\) is calculated using the formula \(W = F\times d\), where \(F\) is force (in newtons, \(N\)) and \(d\) is distance (in meters, \(m\)). The unit of work is the joule (\(J\)). Substituting the units into the formula, we get \(J=N\times m\) (a newton times a meter).

• For "a newton divided by a second": \(N/s\) is not the unit of work. Force \(F = ma\) (\(kg\cdot m/s^{2}\)), so \(N/s=(kg\cdot m/s^{2})/s = kg\cdot m/s^{3}\), which is not related to the work formula.
• For "a newton divided by a meter": \(N/m=(kg\cdot m/s^{2})/m=kg/s^{2}\), not related to work.
• For "a newton times a second": \(N\cdot s=(kg\cdot m/s^{2})\cdot s = kg\cdot m/s\), which is the unit of momentum (\(p = mv\), \(kg\cdot m/s\)), not work.

Answer:

a newton times a meter