Mechanical engergy, energy conservation

In summary, the problem involves a 10-kg block released from point A on a frictionless track with a 3.0 meter portion of friction between points B and C. The block collides with a 2-kg block after passing through BC and they travel together until hitting a spring. The question asks for the velocity of the block after it passes BC. The attempt at a solution involved using equations such as work and energy to calculate the velocity, but the second block is not a part of the motion at point C.
  • #1
Gewitter_05
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Homework Statement


A 10-kg block is released from point A. The track is frictionless except from the portion between B and C which has a length of 3.0 meters. The block travels down the track, passes through BC and first collides with a small block (m=2kg), then they travel together and later hit the spring.

Q: Find the velocity of the block after it passes BC

There were two questions before it, find the velocity of the block when it reaches point B at the bottom of the track and it's 8.85m/s then I found the work between B and C which is -88.2 J. I tried setting up different equations to find the velocity after it passes B and C, but I am missing something.

Homework Equations


Wf=E2-E1
E2=E1
1/2mv^2, mgh, 1/2kx^2, mgx

The Attempt at a Solution


I tried setting the equation equal to the work, -88.2=1/2V^2(m+m), I recently tried -2μkgd=mv2^2-(mv1^2+2mgh1). I am not sure if I am supposed to have the second block in there or not.
 

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  • #2
For the velocity at point C, the second block does not matter - it is not a part of the motion yet.
You probably have the energy of the first block at point B as intermediate result. If it loses 88.2J, what is its energy at point C? This allows to calculate the velocity.
 

FAQ: Mechanical engergy, energy conservation

What is mechanical energy?

Mechanical energy is the sum of potential energy and kinetic energy in a system. Potential energy is the energy stored in an object due to its position or configuration, while kinetic energy is the energy of motion. In simpler terms, mechanical energy is the energy that an object has because of its movement or position.

How is mechanical energy conserved?

According to the law of conservation of energy, energy cannot be created or destroyed, it can only be transformed from one form to another. In the case of mechanical energy, it can be converted from potential energy to kinetic energy and vice versa, but the total amount of mechanical energy in a closed system remains constant. This means that mechanical energy is always conserved in a system.

What are some examples of mechanical energy?

Some common examples of mechanical energy are a swinging pendulum, a rolling ball, a moving car, and a spinning top. In all these cases, mechanical energy is being converted from potential to kinetic and vice versa.

How is mechanical energy measured?

Mechanical energy is measured in joules (J). The amount of mechanical energy an object has depends on its mass, speed, and height. The formula for calculating mechanical energy is E = mgh + 1/2mv^2, where m is the mass of the object, g is the acceleration due to gravity, h is the height, and v is the velocity.

What are the real-world applications of energy conservation?

Energy conservation has many real-world applications, such as reducing energy costs, promoting sustainability, and minimizing the impact on the environment. It is used in industries to improve efficiency and reduce waste, in transportation to improve fuel efficiency, and in homes to reduce energy consumption. Energy conservation is also important for preserving our natural resources and reducing our carbon footprint.

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