Question

Compute the power at which a butterfly of mass 1.0 g will move upward at a rate of 0.5 $m{s}^{-1}$ against the force of gravity? (given $g=10m{s}^{-2}$)

• A. $5W$
• B. $5\times {10}^{-1}W$
• C. $5\times {10}^{-3}W$
• D. $5\times {10}^{-2}W$

Answer 1

Answer: (C)

$5\times {10}^{-3}W$

$Power$ $=mg\times velocity,g=10m{s}^{-2}$
$=\frac{1}{1000}\times 10\times 0.5$
$=\frac{0.5}{100}W=5\times {10}^{-3}W$