Answer:
a) [tex]\Delta W = 180000\,lbf\cdot ft[/tex], b) [tex]AMA = 6[/tex], c) [tex]l = 90\,ft[/tex]
Explanation:
a) The work required to lift up the stone is:
[tex]\Delta W = (12000\,lbf)\cdot (15\,ft)[/tex]
[tex]\Delta W = 180000\,lbf\cdot ft[/tex]
b) The actual mechanical advantage required by the machine is:
[tex]AMA = \frac{12000\,lb}{2000\,lb}[/tex]
[tex]AMA = 6[/tex]
c) The length of the ramp is:
[tex]l = AMA \cdot h[/tex]
[tex]l = 6\cdot (15\,ft)[/tex]
[tex]l = 90\,ft[/tex]
