Attempt: How to Calculate Acceleration in Pulley Systems

In summary: In problem 3, the two masses are in an equilibrium. If you push on one end, the other end will also push back with the same force. So the acceleration will be zero.
  • #1
starprincess
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0
Hello Everyone,
I am having difficulty with these selected problems. Attached is a link to the diagram in reference to each problem. I would truly appreciate your help! Thank you!

1. In Fig.1 the scale at the left is attached to the ceiling and a mass of 1.00 kg hangs from it. It reads 9.81 N. The identical scale at the right is connected by perfect strings passing over perfect pulleys to two 1.00 kg masses hanging vertically at the end of the strings. The scale at the right reads:
a) exactly 9.81 N
b) more than 9.81 N, but not quite as much.
c) less than 9.81 N.
d) exactly 19.81 N.
e) more than 19.62 N.

http://i82.photobucket.com/albums/j246/starprincess101/DSC01143.jpg"

Attempt: I believe this has something to do with static equilibrium equation and the use of tension? So I am guessing it would be A.2. Two identical masses are attached by a light string that passes over a small pulley, as shown in Fig.2. The table and the pulley are frictionless. The masses are moving:
a) with an acceleration less than g.
b) at constant speed.
c) with an acceleration greater than g.
d) with an acceleration equal to g.

Attempt: I think it would be constant speed.http://i82.photobucket.com/albums/j246/starprincess101/DSC01144.jpg" 3. Two masses are connected by a string which goes over an ideal pulley as shown in Fig. 3. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0 degrees to the horizontal. The coefficient of the kinetic friction between block A and the plane is 0.400. Block B has a mass of 2.77 kg. What is the acceleration of the blocks?
a) 0.392 m/s2
b) 1.96 m/s2
c) 3.12 m/s2
d) 5.35 m/s2
e) 0

Attempt: I have no idea how to solve this problem or where to start because I have never learned about inclinations yet.

http://i82.photobucket.com/albums/j246/starprincess101/DSC01145-1.jpg"
 
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  • #2
Your diagrams are far too small to read!
Also, you must show your attempt to do the problems before we can help you.
 
  • #3
Fixed pictures!
 
  • #4
In problem one, the two scales are doing exactly the same job. The weight on the left pulley is holding the scale while the weight on the right pulls on it with 9.81 N. You might think it would read 2x9.81 in both cases because there is 9.81 pulling on each end, but the scale is designed to read just 9.81 N.

For problem 2, you must do some calculations. Think of the two masses and the string as one object that may have an acceleration to the right and down (always in the direction of the string).
The sum of the forces in the direction of the string must equal ma.
Have a go at it - add up all the forces acting that way and put " = ma" on the end!
Show us what you get and we'll check it out for you.
 

FAQ: Attempt: How to Calculate Acceleration in Pulley Systems

1. How do I determine the mechanical advantage of a pulley system?

The mechanical advantage of a pulley system is calculated by dividing the output force by the input force. For a simple pulley system, the mechanical advantage is equal to the number of ropes supporting the load. For more complex systems, you can use the formula MA = 2n, where n is the number of rope segments supporting the load.

2. Can a pulley system increase the efficiency of lifting heavy loads?

Yes, a pulley system can increase the efficiency of lifting heavy loads. By using multiple pulleys, the load is distributed over a larger number of ropes, reducing the amount of force needed to lift the load. This makes it easier to lift heavy objects and can also reduce the risk of injury.

3. How does the direction of the force change in a pulley system?

In a simple pulley system, the direction of the force remains the same. However, in a compound pulley system, the direction of the force alternates between up and down as the rope passes through different pulleys. This allows for a larger mechanical advantage and makes it easier to lift heavy loads.

4. What is the difference between a fixed and a movable pulley?

A fixed pulley is attached to a stationary object, while a movable pulley is attached to the object being lifted. In a fixed pulley, the direction of the force remains the same, while in a movable pulley, the direction of the force changes as the object is lifted.

5. How does friction affect the efficiency of a pulley system?

Friction can reduce the efficiency of a pulley system by converting some of the input energy into heat. This can cause the ropes to wear out more quickly and can also make it more difficult to lift heavy loads. To reduce the effects of friction, lubrication can be used on the pulley wheels and ropes.

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