II. 1-3 handwritten then box the final answers

I. Mimi is traveling 62m 12" South of East and then 37m 8" West of North. At the end of this journey, she asks you for help. A. What is her resultant vector? B. How far and in what direction do you tell her to go so that she can get back to her initial position? Set A will contain UAM Problem while Set A2 will contain the Freefall problem 2. The driver of a car slams on the brakes when he sees a tree blocking the road. The car slows down, and screeches with an acceleration of 5.60 meters per second squared for 4.20 s, making straight skid marks 62.4 m long, all the way to the tree. A. Sketch a diagram for this one-dimensional motion, explicitly indicating the variables, whether known or unknown. (6 points) B. What variable should you solve a value for, in order to determine whether the car hits the tree or not (2 points) C. Did the car hit the tree or not? Why? (6 points) D. Determine the velocity of the car just before the driver stepped on the brake. (6 points) 3. A rocket takes off vertically from the launchpad with no initial velocity but a constant upward acceleration of 2.25 m/s2. At 15.4 s after blastoff, the engines fail completely so the only force on the rocket from then on is the pull of gravity. Neglect the air resistance and other dissipative forces. A. What is the maximum height that the rocket will reach above the launchpad? [8 points] B. How fast is the rocket moving at the instant before it crashes onto the launchpad? [8 points] C. How long after engine failure does it take for the rocket to crash onto the launchpad? [4 points] SOLUTION for UAM Problem 1. The driver of a car slams on the brakes when he sees a tree blocking the road. The car slows down, and screeches with an acceleration of 5.60 meters per second squared for 4.20 s, making straight skid marks 62.4 m long, all the way to the tree. a. Sketch a diagram for this one-dimensional motion, explicitly indicating the variables, whether known or unknown. (6 points) b. What variable should you solve a value for, in order to determine whether the car hits the tree or not. Final velocity (2 points) c. Did the car hit the tree or not? Why? The car hit the tree because v, , is not zero.(6 points) d. Determine the velocity of the car just before the driver stepped on the brake. V initial = 26.6 m/'s (6 points) Var = V, + at =v, +(-5.60 m/s')(4.20 s) x, - x, = =(v. +v.)t 62.4 m = - (v. + v.)(4.20s) Solve simultaneously: vfinal = 3.10 m/s; v initial = 26.6 m/s