Problem on Conservation of energy

So you need to include both blocks in your equations, and set them equal to each other. The final velocity should be the same for both blocks. In summary, the conversation discusses the problem of two connected blocks on a frictionless incline and pulley system. The goal is to determine the final velocity of the blocks after one has slid a distance of 0.25m. The conversation includes the relevant equations and notes where the attempt at a solution went wrong. The correct answer is 1.51 m/s.
  • #1
scytherz
11
0

Homework Statement



Two blocks, A and B (mA=50 kg and mB=100 kg), are connected by a string as
shown. If the blocks begin at rest, what will their speeds be after A has slid
a distance d = 0.25 m? Assume the pulley and incline are frictionless.

Homework Equations



K= .5mv^2
P=mgh
ke(initial) + pe(initial) = kef = pef


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The Attempt at a Solution



.5mvi^2 + mghi = .5mvf^2 + mghf (at rest)
.5mvf^2 = -mghf
.5(50 kg) vf^2 = -100(-9.8)(.25sin37)
vf = 2.42 m/s which is wrong... where did i go wrong? the ans. is 1.51 m/s
 
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  • #2
You have your vf and vi mixed up, but beyond that, do not forget that both blocks have a change in their potential and kinetic energies.
 

FAQ: Problem on Conservation of energy

What is conservation of energy?

Conservation of energy is a fundamental law of physics that states that energy cannot be created or destroyed, but can only be transferred from one form to another.

Why is conservation of energy important?

Conservation of energy is important because it allows us to understand and predict the behavior of systems in the physical world. It also helps us to make more efficient use of resources and reduce waste.

What are some examples of conservation of energy?

Some examples of conservation of energy include a pendulum swinging back and forth, a ball rolling down a hill, and a roller coaster moving along its track. In each of these cases, energy is converted from one form to another, but the total amount of energy remains constant.

What are the different forms of energy?

The different forms of energy include kinetic energy (energy of motion), potential energy (stored energy), thermal energy (heat), chemical energy (stored in chemical bonds), and nuclear energy (stored in the nucleus of an atom).

How does conservation of energy relate to the environment?

Conservation of energy is closely related to environmental issues because it can help us to reduce our energy consumption and minimize our impact on the environment. By understanding how energy is transferred and transformed, we can develop more sustainable energy sources and reduce the negative effects of energy production on the planet.

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