Question

a boat is moving through water at the rate of 8ms. its engines have a horesepower of 75. find the resistence being offered by the water to the motion of the boat?

Answer 1

Power = Force × Velocity
= 2000 N × 8 m/s
= 8000 Watt
= 8 kW

Power of engine is 8 kW

Answer 2

Correct Question:

A boat is moving through the water at the rate of 8m/s. its engines have a horsepower of 75. find the resistance being offered by the water to the motion of the boat?

Answer:

6993.8N

Explanation:

Power of boat = 75 hp

Power of boat = 75 × 746 W --------> equation (i)

The engine of the boat may work at the rate of 75 × 746 J/s.

Let the R be the resistance offered by the water.

$\implies \sf \: velocity \: of \: boat = 8 {ms}^{ - 1}$

$\implies \sf \:power \: of \: engine = R \times v$equation (2)

$\implies \sf \:8R \:$

From equation i and ii we can write,

$\implies \sf \:8R = 75 \times 746$

$\implies \sf \:R = \dfrac{75 \times 746}{8}$

$\implies \sf \:r = 6993.8N$

• Work is said to be done if a body moves through a certain distance under the application of some force.

• W = F × S The rate of doing work is called power. $\sf \: \: \: \: \: \: \: P = \dfrac{ Work \: done } {Time \: taken}$

• The change of one form of energy to another form is called the transformation of energy.