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 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum Apr 22nd 2018, 10:16 PM #1 Member   Join Date: Apr 2017 Location: Turkey Posts: 46 Power Calculations Hello everybody Could you help me to solve this question ? Best regards Razi   Apr 23rd 2018, 05:30 AM #2 Senior Member   Join Date: Aug 2010 Posts: 389 Since you use the term "drag coefficient" can we assume that you know what it means? According to Wikipedia, the drag coefficient is given by $\displaystyle c_d= \frac{2F_d}{\rho u^2A}$ where $\displaystyle c_d$ is the drag coefficient, $\displaystyle F_d$ is the drag force, $\displaystyle \rho$ is the density of the fluid, u is the speed through the fluid, and A is the cross section area. You are asked for the drag force so solve for that: $\displaystyle F_d= \frac{c_d\rho u^2A}{2}$. You are given that A= 400 square cm. and $\displaystyle c_d= 0.6$. You will need to look up the density of air and water and calculate u, the speed of an object moving at 1000 rev/min around a circle of radius $\displaystyle 10 sin(120^o)$.   Apr 24th 2018, 06:30 AM #3 Member   Join Date: Apr 2017 Location: Turkey Posts: 46 Thanks Dear HallsofIvy for your help Best regards  Tags calculations, power Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post DeanReeday Advanced Mechanics 0 Oct 6th 2017 06:32 AM Azureilai Kinematics and Dynamics 1 Dec 3rd 2012 12:46 AM Paul46 Electricity and Magnetism 4 Sep 26th 2009 08:38 AM Fairydust07 General Physics 1 Apr 19th 2009 07:03 PM firemonkey Advanced Mechanics 1 Aug 29th 2008 07:20 PM