Question

The force required to tow a boat over the sea is proportional to the speed of the boat. It is found that it takes 24 H.P. to tow a certain boat at a speed of 4 km/hr. If one wishes to tow boat at a speed of 8 km/hr, the required H.P is…?

• A. 115 HP
• B. 246 HP
• C. 96 HP
• D. 196 HP

Answer 1

The correct option is C 96 HP

$Power,P=FvButF=kvP=k{v}^2=24=k(4{)}^2\dots \dots (1)P=k(8{)}^2\dots \dots \left(2\right)Dividing\left(2\right)by\left(1\right)\therefore \frac{P}{24}={\left(\frac{8}{4}\right)}^2=4P=96H.P.$