Energy Problem, Inclined plane, friction and spring Please help

In summary: As it slides down the inclined plane, the kinetic energy is converted to potential energy because of the angle (wedge). When it reaches the end of the inclined plane, the potential energy is equal to the kinetic energy (since the block has stopped moving). So: Etot=(F1 x 4 m) + (-Ffr x 1)= (-4.92 J) + (1kg x 9.81 m/s^2 x 1m x .6)=.821 J
  • #1
Addie
9
0
An object with mass 1 kg slides down a frictionless inclined plane of length 4 m set at an angle of 30 degrees. It then slides across a flat surface of length 1 m. While sliding across this surface the object experiences sliding friction with the coefficient of sliding friction being .6. It then strikes a spring with a spring constant of 1000 N/m. There is no friction present during the compression of the spring.

What is the maximum compression of the spring, assuming that the object does not stop before hitting the spring?

What is the speed of the object half way across the flat surface?

My answers just don't seem right... but here is my work maybe somebody out there can help...

State 1 is the ramp, there i got
F1= (mg)(sin30)=4.92 N

State 2 is the flat surface:
Etotal= Wc +Wnc
Etot=(F1 x 1 m) + (-Ffr x 1)
Et=(4.92 J) - (1kg x 9.81 m/s^2 x 1m x .6)
Et= -.981 J

State 3 is the spring:
W=1/2 k x^2
-.981 J= 1/2 (1000 Nm) x^2
x= ? because you can't square root negative obviously, so I did somethign wrong and suposeably the correct answer is x=.1655 m and v=5.77 m/s...but I want to figure out how to do the problem, becuase it seems I am not doing it right please help someone thanks...
 

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  • #2
Addie said:
State 2 is the flat surface:
Etotal= Wc +Wnc
Etot=(F1 x 1 m) + (-Ffr x 1)

Here's your mistake. It should be:
Etot=(F1 x 4 m) + (-Ffr x 1)

The question says the inclined plane is 4m long, so F1 works through 4 m.
 
  • #3
I thought that at first, but as the the block is moving along the the flat surface doesn't that force act on the 1 m flat surface not the incline surface?
 
  • #4
Think in terms of energy. The initial energy is potential: [itex]mgh = mgd sin\theta[/itex]. That's the energy the block has as it begins its horizontal slide.
 

1. What is the definition of energy problem?

Energy problem refers to the difficulty or challenge in finding efficient and sustainable sources of energy to meet the growing demands of society. It also involves identifying and addressing issues such as energy production, distribution, and consumption.

2. How does an inclined plane affect energy?

An inclined plane can decrease the amount of energy needed to move an object from one point to another by reducing the force required to lift the object against gravity. This is because the inclined plane increases the distance over which the force is applied, making it easier to move the object.

3. What role does friction play in energy problems?

Friction is a force that opposes motion and causes energy loss. In energy problems, friction can decrease the efficiency of energy conversion and increase the amount of energy needed to perform a task. It is important to reduce friction in order to improve the efficiency of energy use.

4. How does a spring store and release energy?

A spring stores energy when it is compressed or stretched, as it creates potential energy. When released, the stored energy is converted into kinetic energy, causing the spring to move. This energy can be harnessed and used for various purposes, such as in mechanical devices or as a source of renewable energy.

5. What are some solutions to energy problems?

Some solutions to energy problems include using renewable energy sources such as solar, wind, and hydro power, improving energy efficiency through technological advancements, and implementing sustainable practices and policies. It is also important for individuals to reduce their energy consumption and adopt sustainable habits in their daily lives.

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