Physics Help Forum Friction problem

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Jan 4th 2009, 10:56 AM #1 Member   Join Date: Sep 2008 Posts: 42 Friction problem Someone slides down a ramp at 55 degrees. The coefficent of friction is 0.15. The mass of the person is 35 kg. If he starts from rest at the top, how long does it take for him to get to the bottom of the 10.0 m ramp? Could someone help me please?
 Jan 7th 2009, 05:17 PM #2 Junior Member   Join Date: Oct 2008 Posts: 12 $\displaystyle *ma_x = -mgsin(\theta) + f = -mgsin(\theta) + \mu N$ $\displaystyle ma_y = N - mgcos(\theta) = 0$ From that $\displaystyle ma_x = -mgsin(\theta) + \mu mgcos(\theta)$ $\displaystyle a_x = g(\mu gcos(\theta)-sin(\theta))$ Now you should know $\displaystyle \Delta s = \frac{at^2}{2}$ Solve for t
 Jan 8th 2009, 02:28 AM #3 Junior Member   Join Date: Jan 2009 Posts: 5 physics help tutorials dear i want to say only one thing regarding urgent physics tutorials to go through to various e learning of physics programs in internet, where you can increase your physics skills.

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