Question

15) Mike is in his car on his cell phone (hands free of course), he says his acceleration is zero, what do you know about the cars motion? (Be careful, Canvas will not have the same order for the answers below!) The car can only be stopped. The car can only be moving with a constant velocity The car could be stopped or moving with a constant velocity The car is slowing down The car is speeding up The car could be either slowing down or speeding up. 16) A ball is thrown straight up in the air with an initial velocity of 40 m's, assume the ball is in free fall and is accelerating at a rate of approximately , - - 10 m/s, what is the approximate velocity of the ball after 3 seconds? 17) A jet airplane (mza = 4,000 kg) speeds up in three-dimensional space for 5 seconds, the jets initial and final velocities are given below, what is the magnitude of the jets acceleration and what is the net force acting on the jet as it accelerates? F = (+ 40 m/s)X + (+30m/s)9+(+20m/s)2 v = ( + 10 m/s)X + (0 m/s)ý + (+10 m/s)2 18) A ball is attached to a string and moves in a horizonal circular path at a constant speed in the counterclockwise direction. Identify the directions of the velocity vector and acceleration vector from the choices below. Page 5 of 7

Answer 1

(15) (c) The car could be stopped or moving with a constant velocity, (6) vo at at VE Чо -(10 x3) Va 10 m/s (17) ax= uorlo 6 m/s² کل 30 ay 6 m/s² J а, 20-10 - 2 m/? 8.7178 m/s² a = 6)²+(63² +2² fa 34871,19 4000 x 8.7178 = (18) Va ID B