Problem-Solving: Calculating Forces on Moving Objects [4 Examples]

[momina4468]

Can anyone tell me the answers to these problems because I cannot check them b/c they are not in the back of the book. I attempted them but i feel like they are wrong.

1. a supertanker (mass= 1.70 x 10^8 kg) is moving with a constant velocity. Its engine generates a forward thrust of 7.40 x 10^5 N. Determine (a) the magnitude of the resistive force exerted on the tanker by the water and (b) the magnitude of the upward buoyant force exerted on the tanker by the water.

2. A helicopter is moving horizontally to the right at a constant velocity. The weight of the helicopter is W = 53,800 N. The lift force generated by the rotating blade makes an angle of 21 degrees with respect to the vertical. (a) what is the magnitude of the lift force? (b) determine the magnitude of the air resistance that opposes the motion.

3. A circus clown weights 890 N. The coefficient of static friction between the clown's feet and the ground is .53. He pulls vertically downward on a rope that passes around three pulleys and is tied around his feet. What is the minimum pulling force that the clown must exert to yank his feet out from under himself?

4. A 43.8 kg sign is suspended by two wires. Wire one makes a 43 degree angle with respect to the ceiling and wire 2 makes a 55 degree angle with the ceiling. Find the tension in wire 1 and wire 2.

 

[hage567]

Show us your solutions. We will tell you if you are doing them correctly. We won't do the work for you.

 

[baba89]

Hello,

I cannot provide the answers to these problems as it goes against the principles of scientific inquiry. However, I can guide you through the problem-solving process so you can check your own work.

1. In order to determine the magnitude of the resistive force and the upward buoyant force, we need to use Newton's Second Law of Motion, which states that the net force on an object is equal to its mass multiplied by its acceleration. Since the tanker is moving with a constant velocity, its acceleration is zero, so the net force must also be zero.

(a) To find the magnitude of the resistive force, we can use the formula: resistive force = mass x acceleration. Since the acceleration is zero, the resistive force must also be zero. This means that the force applied by the engine is balanced by an equal and opposite force from the water.

(b) The buoyant force exerted on an object is equal to the weight of the displaced water. Since the tanker is floating, the buoyant force must be equal to its weight. Using the formula: buoyant force = density x volume x acceleration due to gravity, we can determine the volume of water displaced by the tanker. Then, using the density of water, we can calculate the magnitude of the buoyant force.

2. For this problem, we need to use trigonometry to break down the lift force into its vertical and horizontal components. The vertical component will be equal to the weight of the helicopter, while the horizontal component will be equal to the air resistance.

(a) To find the magnitude of the lift force, we can use the formula: lift force = weight / sin(theta), where theta is the angle between the lift force and the vertical. In this case, theta is 21 degrees. Once we have the magnitude of the lift force, we can use trigonometry to find the horizontal component, which will also be the air resistance.

3. In this problem, we need to consider the forces acting on the clown. The minimum pulling force required to yank his feet out from under himself will be equal to the maximum static friction force. This can be calculated using the formula: maximum static friction force = coefficient of static friction x normal force. The normal force in this case will be equal to the weight of the clown.

4. To find the tension in the wires, we can use the fact that the net force in the vertical direction must be