Problem 6.61 An outboard motor for a boat is rated at 33 hp . Part A If it can m
ID: 3160748 • Letter: P
Question
Problem 6.61 An outboard motor for a boat is rated at 33 hp . Part A If it can move a particular boat at a steady speed of 30 km/h , what is the total force resisting the motion of the boat? Problem 6.61 An outboard motor for a boat is rated at 33 hp . Part A If it can move a particular boat at a steady speed of 30 km/h , what is the total force resisting the motion of the boat? Problem 6.61 An outboard motor for a boat is rated at 33 hp . Part A If it can move a particular boat at a steady speed of 30 km/h , what is the total force resisting the motion of the boat?Explanation / Answer
According to the given problem,
As the boat moving at a constant speed the magnitude of the force that the motor is exerting on the boat is equal to the magnitude of the total resisting force. To determine the force that the motor is exerting on the boat, we must use the following equation for power.
Power = Force * velocity
According to a table in my physics book, 1 hp is 746 watts
Power = 33 * 746 = 24,618 watts
Let’s convert the velocity from km/h to m/s.
1 km = 1000 m, 1 h = 3600 s, 1 km/h = 1000/3600 = 5/18 m/s, v = 30 * 5/18
The velocity is approximately 8.33 m/s.
Power = Work ÷ time
Work = Force * distance
Power = Force * distance ÷ time
distance ÷ time = velocity
Power = Force * velocity
24,618 = Force * 8.333
Force = 23,126 /8.33
The force is approximately 2954.16 N.