PHYS 114 Midterm: 114 MT2 Tutorial Soln
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Name ______________________________________ student id _______________ score________ last first. [25 points total] two balls, a and b, are placed at the top of different frictionless ramps as shown. They are released from rest at the same height from the ground. The masses of a and b are the same. B h: [5 pts] draw a qualitatively correct free- body diagram for each ball on ramps 1 and 2 at an instant when it is traveling down the track. Clearly label each force to indicate (1) the type of force, (2) the object exerting the force, and (3) the object on which the force is exerted. Since (cid:1849)(cid:3404)(cid:1832) (cid:1871)cos(cid:2016) , the normal forces on both balls are perpendicular to their displacements, so cos90 (cid:3404)0, so the work done by the normal force in each case is zero. Using conservation of energy, the net work done by external forces on the ball is equal to the change in kinetic energy of the ball.
