Problem 25PE

Repeat Exercise 9.24 for the pulley shown in Figure 9.26(c), assuming you pull straight up on the rope. The pulley system’s mass is 7.00 kg .

Figure 9.26 (b) Three pulleys are used to lift a load in such a way that the mechanical advantage is about 3. Effectively, there are three cables attached to the load.

Exercise 9.24:

If you used an ideal pulley of the type shown in Figure 9.26(a) to support a car engine of mass 115 kg , (a) What would be the tension in the rope? (b) What force must the ceiling supply, assuming you pull straight down on the rope? Neglect the pulley system’s mass.

Figure 9.26 (a) The combination of pulleys is used to multiply force. The force is an integral multiple of tension if the pulleys are frictionless. This pulley system has two cables attached to its load, thus applying a force of approximately 2T . This machine has MA ≈ 2 .

Step 1 of Step 3</p>

A car engine is lifted up by using the ideal pulley and the free body diagram is given below.Given the mass of the engine is 115 kg. Pulley, system mass is 7 kg.

Step 2 of Step 3</p>

Now we have to find the tension in the rope by ignoring the slight angles which make the rope vertical. From the free body diagram of the lower pulley, we equate the vertical force to be zero, hence we get.

where T=tension, m=mass of the car engine, mp= mass of the pulley, and g=acceleration.

398.5N is the tension in the rope

Step 3 of