How much work does a pulling force of 40, N do on 20, kg box in pulling it 8, m across smooth floor

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5.Work, Energy, Power and Collision

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How much work does a pulling force of $40\, N$ do on the $20\, kg$ box in pulling it $8\, m$ across the smooth floor at a constant speed. The pulling force is directed at $60^o$ above the horizontal .............. $\mathrm{J}$

A

$160$

B

$277$

C

$784$

D

None of the above

Solution

$\mathrm{W}=\mathrm{F} \cdot \mathrm{S} \cdot \cos \theta$

$=40 \times 8 \times \cos 60^{\circ}=40 \times 8 \times \frac{1}{2}$

$=160 \mathrm{J}$

Standard 11

Physics

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