Determine the speed of the block EPE

In summary, The block is attached to a horizontal spring with a constant 19.6 N/m. When a constant 20 N horizontal force is applied, the spring stretches and the block moves 0.900 m from equilibrium on a frictionless surface. To determine the speed of the block, the equations PE=1/2kx^2 and E=1/2mv^2 were used, resulting in a speed of 2.52 m/s. However, this calculation did not take into account the 20 N force being applied to the block, which would affect the overall energy of the system. The constant force being applied also implies a net force acting on the block.
  • #1
physics1234
21
0
A 2.5 kg block at rest on a tabletop is attached to a horizontal spring having constant 19.6 N/m. The spring is initially unstretched. A constant 20 N horizontal force is applied to the object, causing the spring to stretch. Determine the speed of the block after it has moved 0.900 m from equilibrium if the surface between the block and tabletop is frictionless.

I used PE=1/2kx^2 and got 7.938

Then, I used E=1/2mv^2 and plugged 7.938 in for E and solved for v. I found v to be 2.52.

I tried the problem another way and got the same answer, I don't understand why it's wrong.
 
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  • #2
Because you are completely ignoring the 20N force that is applied to the object.
 
  • #3
How would I work that into the solution?
 
  • #4
In line 2 of your solution you state that the potential energy of the spring is exactly equal the total energy of the system. Is that correct? Is there any other forces acting on the block other than the spring? How about that constant horizontal force being applied to the block? Is this force in the same direction as the potential force?

Also note that it says constant force is being applied to the block. Which tells us what about acceleration? This implies net force = _______ .
 
Last edited:

What is the block EPE?

The block EPE refers to the Energy Potential Energy of a system, which is the stored energy that an object has due to its position or condition. In this case, the block EPE refers to the potential energy of a block.

What is the speed of the block EPE?

The speed of the block EPE refers to the rate at which the block is moving. It is usually measured in meters per second (m/s) or kilometers per hour (km/h).

How is the speed of the block EPE determined?

The speed of the block EPE can be determined by dividing the distance traveled by the time it took to travel that distance. This calculation is known as speed = distance/time.

What factors affect the speed of the block EPE?

The speed of the block EPE can be affected by various factors such as the force applied to the block, the mass of the block, and the surface on which the block is moving. Other factors such as air resistance and friction can also affect the speed of the block EPE.

Why is it important to determine the speed of the block EPE?

Determining the speed of the block EPE can help in understanding the energy and motion of the block. It can also be used to analyze and predict the behavior of the block in different situations, making it a crucial factor in many scientific experiments and real-life applications.

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