Question

A person lifts a package weighing 75N. If she lifts at 1.2M off the floor,what work has she done?

Answer 1

Answer:

• Force (F) = 75 N
• Displacement (s) = 1.2 m
• Work done = ?

Work done (W) by a constant force (F) on a particle/object which undergoes displacement (s) is given by ;

$\longrightarrow\rm W = Fs \cos(\theta)$

Here, the force and the displacement acting in the same direction.therefore, cos θ will be (0°)

$\longrightarrow\rm W = 75 \times 1.2 \times \cos( {0}^{ \circ} )$

$\longrightarrow\rm W = 75 \times 1.2 \times 1$

$\longrightarrow \underline{ \underline{ \red{\rm W = 90 \: J}}}$

• Dimensional formula of work done is [ML²T-²]
• S.I unit of work is Joule (J)
• CGS unit is erg
• 1 Joule = 10⁷ erg