PH 125 Midterm: ph125_ex1_practice_SOLN
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Random sample problems: the position of a particle in meters can be described by x = 10t 2. 5t2, where t is in seconds. When it changes direction, its velocity is zero. Find the time at which that is true, evaluate the position there. v = dx dt. The t = 0 position is x = 0. We need to nd another time for which x = 0 and evaluate the velocity there. x = 10t 2. 5t2 = t(10 2. 5t) = 0 v(4 s) = 10 m/s. = t = {0, 4 s: a projectile is launched with an initial velocity of ~v = (17 + 3. 0 ) m/s. We are given the launch velocity in component form, ~v = vx + vy . The angle is simply tan = vy vx. 17 10 : how far does the projectile above travel in the direction, assuming that gravity acts in the direction? (i. e. , what is the range of the particle?)
