Posted by **Casey** on Thursday, January 12, 2012 at 6:47pm.

Could someone verify the answers. I don't know question C and D

Thank you!

1. In physics, the formula for centripetal force is F =

mv^2/

r

where m is the mass, v the velocity, and r the radius.

a) Find the length of a string when a mass of 2.4kg is being spun at a speed of 5 m/sec if the centripetal force

is 15.8 N. Round your answer to the nearest tenth.

Answer: 3.8m

----------------------------------------

b) What length would the string need to be to increase the force to 20.5 N if the speed is 5 m/sec and the

mass is 2.4 kg?

Answer: 2.9m

---------------------------------------

c) If the string is made longer, but the mass and velocity are kept the same, how will this effect the force?

d) What would be the effect on the centripetal force if the mass and velocity were kept the same and the

length of the string was doubled?

- Math -
**Steve**, Friday, January 13, 2012 at 4:21am
a and b are ok

since F varies directly with m and v^2, but inversely with r, increasing r decreases F, as you see if you compare the answers to a and b.

since F varies directly with m and v^2, but inversely with r, doubling r halves F.

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