#$&*
Phy 201
Your 'cq_1_25.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A steel ball of mass 110 grams moves with a speed of 30 cm / second around a circle of radius 20 cm.
• What are the magnitude and direction of the centripetal acceleration of the ball?
answer/question/discussion: ->->->->->->->->->->->-> :
Fcent = v2 / r
Fcent = (30 cm)2 / 20 cm = 1.5 cm/s/s
@& v = 30 cm/s, not 30 cm
30 cm / 20 cm is not 1.5 cm / s / s. The units don't match. Also v is squared.
v^2 = (30 cm)^2 = 900 cm^2, so v^2 / rs much greater than 1.5 cm/s^2.*@
#$&*
• What is the magnitude and direction of the centripetal force required to keep it moving around this circle?
answer/question/discussion: ->->->->->->->->->->->-> :
a = 1.5 cm/s/s
F = mv2 / r
F = 110g * 1.5 cm/s/s = 165 g*cm/s/s
@& If a was 1.5 cm/s/s this would be correct. However a is not 1.5 cm/s/s.*@
#$&*
@& You didn't evaluate the expression correctly. The units should have tipped you off.
This will be easy to fix, but be sure you understand how the units work out.
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