Calculating Forces and Work in Crate Displacement

In summary, the magnitude of F needed to move the crate is 2,254 N. The total work done on the crate is 9,016 J, with 27,312 J done by gravity and -18,296 J done by the pull of the rope. The work done by F on the crate is 54,624 J. The work of F is not equal to the product of the horizontal displacement and the answer to A because of the vertical displacement and other forces acting on the crate.
  • #1
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A 230 kg crate hangs from the end of a rope length L=12.0 m. You push horizontally on the crate with a varying force F to move it distance d=4.00m to the side.
A: What is the magnitude of F when the crate is in this final position? During the crate's displacement, what are B:the total work done on it, C:the work done by the gravitational force on the crate, and D: the work done by the pull on the crate from the rope? E: Knowing that the crate is motionless before and after its displacement, use the answers to B, C, and D to fine the work your force F does on the crate. F: Why is the work of your force not equal to the product of the horizontal displacement and the answer to A?

I am clueless...please help!
 
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  • #2
A: The magnitude of F is equal to the weight of the crate, W=mg=230 kg x 9.8 m/s^2 = 2,254 N. B: The total work done on the crate is equal to the product of the force and displacement, W=Fd= 2,254 N x 4.00 m = 9,016 J.C: The work done by the gravitational force on the crate is equal to the product of the weight of the crate and the vertical displacement, W=mgΔh= 230 kg x 9.8 m/s^2 x 12.0 m = 27,312 J.D: The work done by the pull on the crate from the rope is equal to the product of the force from the rope and the displacement, W=Fd= (2,254 N - mg)d = 2,254 N x 4.00 m - 230 kg x 9.8 m/s^2 x 12.0 m = -18,296 J.E: The work your force F does on the crate is equal to the total work done on the crate minus the work done by the gravitational force and the work done by the pull on the crate from the rope, W=Wtotal-Wgrav-Wrope = 9,016 J - 27,312 J - (-18,296 J) = 54,624 J. F: The work of your force is not equal to the product of the horizontal displacement and the answer to A because the crate also experiences a vertical displacement. Additionally, the force of gravity and the pull from the rope are also acting on the crate, so these must be taken into account to determine the work your force F does on the crate.
 
  • #3


I can provide a response to this scenario using the principles of force and work. First, let us determine the magnitude of force F when the crate is in its final position. To do this, we can use the equation F = mg, where m is the mass of the crate and g is the acceleration due to gravity. Substituting the given values, we get F = (230 kg)(9.8 m/s^2) = 2254 N.

Next, let us calculate the total work done on the crate during its displacement. Work is defined as the product of force and displacement, so we can use the equation W = Fd. Substituting the values, we get W = (2254 N)(4.00 m) = 9016 J.

Now, let us determine the work done by the gravitational force on the crate. Since the crate is hanging from a rope, the gravitational force is acting downwards, while the displacement is horizontal. Therefore, the work done by the gravitational force is zero, as the force and displacement are perpendicular to each other.

The work done by the pull on the crate from the rope can be calculated using the same equation, W = Fd. However, in this case, the force and displacement are in the same direction, so the work done by the rope is W = (2254 N)(12.0 m) = 27,048 J.

Since the crate is motionless before and after its displacement, the net work done on it is zero. This means that the work done by the force F must be equal to the negative of the work done by the other two forces, i.e., W(F) = -W(gravitational force) - W(rope pull). Substituting the values, we get W(F) = -9016 J - 27,048 J = -36,064 J.

Finally, the work done by your force F is not equal to the product of the horizontal displacement and the answer to A (2254 N) because the force is not acting in the same direction as the displacement. In this case, the force is acting at an angle to the horizontal direction, so only the component of the force in the horizontal direction is doing work. This is why we use the equation W = Fd cosθ, where θ is the angle between the force and the displacement. Therefore, the work done by your force F is W
 

1. How do you calculate the force needed to move a crate?

To calculate the force needed to move a crate, you need to know the mass of the crate and the acceleration it experiences. The formula for force is F=ma, where F is the force in Newtons, m is the mass in kilograms, and a is the acceleration in meters per second squared.

2. How do you calculate the work done when moving a crate?

To calculate the work done when moving a crate, you need to know the force applied to the crate and the distance it is moved. The formula for work is W=Fd, where W is the work in Joules, F is the force in Newtons, and d is the displacement in meters.

3. What is the relationship between force and displacement when moving a crate?

The relationship between force and displacement when moving a crate is directly proportional. This means that as the force increases, the displacement will also increase, and vice versa. This relationship is described by the formula F=ma, where a is the acceleration, which is equal to the change in displacement over time.

4. How do you calculate the net force on a crate?

To calculate the net force on a crate, you need to consider all the forces acting on the crate, both in magnitude and direction. The net force is the sum of all the forces acting on the crate, and it determines the acceleration of the crate according to the formula F=ma.

5. What factors affect the amount of force needed to move a crate?

The amount of force needed to move a crate is affected by the mass of the crate, the coefficient of friction between the crate and the surface it is on, and the angle of the incline (if applicable). Other factors may also include air resistance and the strength of the person or machine moving the crate.

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