Physics

Problem

a. A motorboat experiences a constant backward water resistance of

400\,\text{N}

. Calculate the power needed to maintain a steady speed of

10\,\text{km\,h}^{-1}

. (Use

1\,\text{km\,h}^{-1}=\dfrac{5}{18}\,\text{m\,s}^{-1}

.) b. If the same boat must now travel at

25\,\text{km\,h}^{-1}

under the same resistance, compute the required power. c. How many times greater is the power at

25\,\text{km\,h}^{-1}

compared to that at

10\,\text{km\,h}^{-1}