Calculating work done by friction

• rleung3
W=FsIn summary, the conversation is discussing the calculation of work done by friction on an object that is released from a compressed spring. The s term in W=Fs is typically thought to be equal to the distance the spring is compressed plus the additional distance traveled by the object after leaving the spring. However, in one problem, the s value only equals the distance traveled by the object after surpassing the uncompressed point of the spring. The possibility of a frictionless surface is also mentioned, and it is suggested to use conservation of energy to calculate the amount of work done by friction.
rleung3
Hi,

When you compress a spring and release it (allowing object to spring some distance), to compute the work done by friction, your s term in W=Fs would have to equal the distance that the spring is compressed + the additional distance traveled by the object once it leaves the spring, right?

That's what I alwasy thought, but in one of my problems, it uses an s value that equals ONLY the distance traveled by the object after it surpasses the point of the uncompressed spring.

Ryan

Does it say the surface under the spring is frictionless?

No, it does not...

Do you know the initial velocity after the object is released? You could use conservation of energy to see how much EPE is converted to KE. Whats left over is the work taken out of the system by friction. Then you can add this to what you figure out later

1. How is work done by friction calculated?

The work done by friction can be calculated by multiplying the force of friction by the distance over which it acts. This can be expressed as W = Fd, where W is the work done, F is the force of friction, and d is the distance over which the force of friction acts.

2. What is the unit of measurement for work done by friction?

The unit of measurement for work done by friction is joules (J). This is the same unit used to measure other forms of work and energy.

3. How does the coefficient of friction affect the work done?

The coefficient of friction is a measure of the resistance between two surfaces in contact. The higher the coefficient of friction, the greater the force of friction and therefore the more work is done over a given distance.

4. Is work done by friction always negative?

Yes, work done by friction is always negative because it acts in the opposite direction of the displacement. This means that the work done by friction results in a loss of energy.

5. Can the work done by friction be greater than the initial kinetic energy of an object?

No, the work done by friction cannot be greater than the initial kinetic energy of an object because it is a form of energy loss. The initial kinetic energy is the maximum amount of energy an object has, and friction can only decrease this amount.

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