A sailor pulls a boat horizontally alongside a dock for 10.0 m with an angled rope. He does 766 J of work and has a force of 100.0 N. What was the angle of the rope?
(Points : 3)
30°

40°

50°

60°

Question

A sailor pulls a boat horizontally alongside a dock for 10.0 m with an angled rope. He does 766 J of work and has a force of 100.0 N. What was the angle of the rope?
(Points : 3)
       30°

       40°

       50°

       60°

jim_thompson5910 · Answer

$$\Large w = f*d*cos(\theta)$$ 

$$\Large 766 = 100*10*cos(\theta)$$

solve for theta

anonymous · Answer

i got .17 is that right? @jim_thompson5910

jim_thompson5910 · Answer

no

anonymous · Answer

ops sorry wrong thing i got 60 @jim_thompson5910

jim_thompson5910 · Answer

try solving 766 = 100*10*x for x

jim_thompson5910 · Answer

tell me what you get

anonymous · Answer

I got 1.3 but i think i did it wrong

jim_thompson5910 · Answer

yeah you did

anonymous · Answer

can you explain

jim_thompson5910 · Answer

does this help

766 = 100*10*x

766 = 1000x

?

anonymous · Answer

then dont you divide by 766?

jim_thompson5910 · Answer

you divide both sides by 1000 to move the 1000 over

anonymous · Answer

then you get .766

jim_thompson5910 · Answer

cos(theta) = 0.766

theta = ???

anonymous · Answer

Im not sure how to solve for that

jim_thompson5910 · Answer

apply arccosine to both sides

anonymous · Answer

and i do that by adding x on both sides?

jim_thompson5910 · Answer

what is the arccosine of 0.766?