AngelicTaboo Posted November 21, 2004 Share Posted November 21, 2004 Hi all! was wondering if anybody could help me out with the method for this question..... Ive got a physics for chemists test tommorrow in uni since I havn't done A-Level Physics before. Ive been going through a couple of questions as part of my revision which most of them I have been getting the right answers... Ive just recentely come across this question and its really puzzling me how to get to the right answer.... Question The blades of a rotary lawn mower are 0.25 m in radius and have a maximum rotation rate of 3,700 revoultions per minute. Calculate the velocity at the tip of the blade at the maximum rotation rate. [Answer: 97 m/s] All replies would be gratefully appreciated...Thanks Link to comment Share on other sites More sharing options...
AngelicTaboo Posted November 21, 2004 Author Share Posted November 21, 2004 Hi all! was wondering if anybody could help me out with the method for this question..... Ive got a physics for chemists test tommorrow in uni since I havn't done A-Level Physics before. Ive been going through a couple of questions as part of my revision which most of them I have been getting the right answers... Ive just recentely come across this question and its really puzzling me how to get to the right answer.... Question The blades of a rotary lawn mower are 0.25 m in radius and have a maximum rotation rate of 3,700 revoultions per minute. Calculate the velocity at the tip of the blade at the maximum rotation rate. [Answer: 97 m/s] All replies would be gratefully appreciated...Thanks Link to comment Share on other sites More sharing options...
psi20 Posted November 21, 2004 Share Posted November 21, 2004 Draw a circle with a radius of .25m (or draw a scaled down version of it) Firstly, 1 revolution means going around the circle once. Going around the circle once means traveling its circumference. The circumference of a circle is 2*pi*1/4 m Secondly, the blade goes at 3700 revolutions per minute. Therefore, the blade goes 3700 (2*pi*.25m)/ 1 minute Just convert by multiplying it by (1 minute / 60 seconds) to get m/s units. Take 2 significant digits. Link to comment Share on other sites More sharing options...
psi20 Posted November 21, 2004 Share Posted November 21, 2004 Draw a circle with a radius of .25m (or draw a scaled down version of it) Firstly, 1 revolution means going around the circle once. Going around the circle once means traveling its circumference. The circumference of a circle is 2*pi*1/4 m Secondly, the blade goes at 3700 revolutions per minute. Therefore, the blade goes 3700 (2*pi*.25m)/ 1 minute Just convert by multiplying it by (1 minute / 60 seconds) to get m/s units. Take 2 significant digits. Link to comment Share on other sites More sharing options...
AngelicTaboo Posted November 21, 2004 Author Share Posted November 21, 2004 Awww thank you so much youv'e been a great help! Link to comment Share on other sites More sharing options...
AngelicTaboo Posted November 21, 2004 Author Share Posted November 21, 2004 Awww thank you so much youv'e been a great help! Link to comment Share on other sites More sharing options...
psi20 Posted November 21, 2004 Share Posted November 21, 2004 No problem. Link to comment Share on other sites More sharing options...
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