Question

You wish to lift a 12,000 lb stone by a vertical distance of 15 ft. Unfortunately, you can only generate a maximum pushing force of 2,000 lb.

What is the amount of work you must input
in order to move the stone?

What is the actual mechanical advantage (AMA) required by a machine to complete the work

You build a ramp to create the ideal mechanical advantage. What is the length of the ramp in feet?

Answer 1

Answer: a)

Step-by-step explanation:

Answer 2

a)
`\Delta W = 180000\,lbf\cdot ft`, b)
`AMA = 6`, c)
`l = 90\,ft`

Step-by-step explanation:

a) The work required to lift up the stone is:

`\Delta W = (12000\,lbf)\cdot (15\,ft)`

`\Delta W = 180000\,lbf\cdot ft`

b) The actual mechanical advantage required by the machine is:

`AMA = (12000\,lb)/(2000\,lb)`

`AMA = 6`

c) The length of the ramp is:

`l = AMA \cdot h`

`l = 6\cdot (15\,ft)`

`l = 90\,ft`