SOLUTION: F varies directly with m and inversely with the square of d. if d=4 when F=75 and m=20 find d when F=200 and m=120

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Question 1134732: F varies directly with m and inversely with the square of d.
if d=4 when F=75 and m=20 find d when F=200 and m=120

Found 2 solutions by mathsolverplus, josmiceli:
Answer by mathsolverplus(88) About Me  (Show Source):
You can put this solution on YOUR website!
Attached is the step-by-step solution to your question.
.


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Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +k+ = the constant of proportionality
+F+=+k%2A%28+m%2Fd%5E2+%29+
+d+=+4+
+F+=+75+
+m+=+20+
+75+=+k%2A%28+20%2F4%5E2+%29+
+k+=+%28+75%2A16+%29%2F20+
+k+=+%2875%2A4%29%2F5+
+k+=+15%2A4+
+k+=+60+
-------------------------
+F+=+k%2A%28+m%2Fd%5E2+%29+
+200+=+60%2A%28+120%2Fd%5E2+%29+
+d%5E2+=+%28+60%2A120+%29%2F200+
+d%5E2+=+%28+30%2A120+%29%2F100+
+d%5E2+=+36+
+d+=+6+