Oct 9, 2009 #1 T Teresa Member Joined May 14, 2008 Messages 102 Reaction score 0 Points 16 How far will it coast before rolling back down?
Oct 13, 2009 #2 Q questor New member Joined Aug 2, 2008 Messages 13 Reaction score 0 Points 1 The car goes on until the force of gravity brings it to a stop. .............._/¯¯¯¯\__.Vi26m/s .............OO___----- ____--------|\--- Wsin8° .......................|..\ .......................|8°.\.N The car has a Kinetic Energy directed upwards the slope. The component of Weight of the car parallel to the slope retards the car for a distance S until Vf becomes zero (Vf = 0) KE(final) = KE(initial) - Work(retarding force) ½mVf ² = ½mVi ² - (Wsin8°)S 0 = ½mVi ² - mgsin8°S .........m cancels gsin8°S = ½Vi ² S = Vi ² /2gsin8° S =(26)² /2 (09.8)(.139) S = 248.1 m --------------------------------------------------- Another way is to use KE = PE ………............................….… | ……......................…… ..........| ….................S… ...................| …..........… ............................|h ….... ......8°............................| __________________________| ½mV ² = mgh..........m cancels V ² = 2gh. h = V ² / 2g h = (26)² / 2(9.8) h = 34.49 m sin8° = h / S S = (34.49)/(.139) S = 248.1m
The car goes on until the force of gravity brings it to a stop. .............._/¯¯¯¯\__.Vi26m/s .............OO___----- ____--------|\--- Wsin8° .......................|..\ .......................|8°.\.N The car has a Kinetic Energy directed upwards the slope. The component of Weight of the car parallel to the slope retards the car for a distance S until Vf becomes zero (Vf = 0) KE(final) = KE(initial) - Work(retarding force) ½mVf ² = ½mVi ² - (Wsin8°)S 0 = ½mVi ² - mgsin8°S .........m cancels gsin8°S = ½Vi ² S = Vi ² /2gsin8° S =(26)² /2 (09.8)(.139) S = 248.1 m --------------------------------------------------- Another way is to use KE = PE ………............................….… | ……......................…… ..........| ….................S… ...................| …..........… ............................|h ….... ......8°............................| __________________________| ½mV ² = mgh..........m cancels V ² = 2gh. h = V ² / 2g h = (26)² / 2(9.8) h = 34.49 m sin8° = h / S S = (34.49)/(.139) S = 248.1m