Physics pulley question help please

In summary, the conversation discusses a two body system consisting of a 0.25kg object accelerating on a rough surface and a 0.1kg object suspended over a pulley by a string. The coefficient of kinetic friction is given as 0.183 and the goal is to calculate the acceleration of the block and the tension in the string. The solution involves using the equations Fg=mg, Fnet=ma, and fn=fg=mg to determine the acceleration to be 1.5m/s^2 and the tension to be 0.981N. The conversation also mentions an alternative solution method using the equations mg-Mgu=(m+M)a and T=Ma+Mgu.
  • #1
moe6142
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Homework Statement


Consider the two body system above. There is a 0.25kg object accelerating across a rough surface. The sliding object is attached by a string to a 0.1kg object which is suspended over a pulley. the coefficient of kinetic friction is 0.183. Calculate the acceleration of the block and the tension in the string.

Homework Equations


Fg=mg
Fnet=ma


The Attempt at a Solution



i got the acceleration to be 1.5...m/s^2 i don't know if it is right

fn=fg=mg 0.25 x9.81m/s^2 =2.4525N
ff=ufn
ff=0.183 x 2.4525N =0.4488075 ff=fg since fn=fg

fg2= 0.1 x 9.81 =0.981 then subtracted them to get fnet then divided
 
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  • #2
Let the driving force (weight of the hanging block-friction of the block on the surface)=the combined mass time acceleration. To solve for a.

mg-Mgu=(m+M)a.

The tension in the string should be the force required to drive the block on the surface against friction at a.

T=Ma+Mgu.



*or so I think, it's been a while since I have done such problems.
 

1. How does a pulley system work?

A pulley is a simple machine that uses a wheel with a groove and a rope or cable to change the direction of a force. When a force is applied to one end of the rope, the pulley rotates, and the other end of the rope pulls on the load. This allows for the load to be lifted or moved with less effort.

2. What are the different types of pulleys?

There are three main types of pulleys: fixed, movable, and compound. A fixed pulley has a stationary axle and simply changes the direction of the force. A movable pulley has a movable axle and reduces the effort needed to lift a load. A compound pulley combines both fixed and movable pulleys to increase mechanical advantage.

3. How do I calculate the mechanical advantage of a pulley system?

Mechanical advantage is the measure of how much a machine amplifies the input force. To calculate the mechanical advantage of a pulley system, divide the output force (load) by the input force (effort). For example, if a pulley system has an output force of 100 N and an input force of 20 N, the mechanical advantage would be 100/20 = 5.

4. What is the difference between ideal and actual pulley systems?

An ideal pulley system is one that has no friction or mass, meaning all of the input work is converted directly into output work. In reality, pulley systems have friction, which reduces the efficiency of the system and requires more input work to achieve the same output work. Additionally, the mass of the pulley itself can also affect the mechanical advantage of the system.

5. How does the number of pulleys affect the mechanical advantage?

The number of pulleys in a system can greatly affect the mechanical advantage. In general, the more pulleys a system has, the greater the mechanical advantage. This is because each additional pulley reduces the amount of effort needed to lift a load, making the system more efficient. However, adding too many pulleys can also increase the amount of friction and decrease the efficiency of the system.

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