Dr. S.F. Ahmad Practice EXAM I Sept. 27,2002
Time: 50 min.
NOTE: Please answer all the
questions. Show your working or explain
your answer for partial credits. An
answer without any work shown or without any explanation is worth zero points.
NAME:____________________________________________
Q.1 A hot-air balloon is traveling vertically upward at a constant seed of 5.00 m/s. When it is 21.00 m above the ground, a package is released from the balloon.
(a) [2] What is the initial velocity of the package?
(b) [5] For how long after being released is the package in the air?
(c) [3] What is the velocity of the package just before impact with the ground?
Q.2[10]. A roller coaster car moves 80 m horizontally and then travels 42 m at an angle of 30.0o above the horizontal. It then travels 45 m at an angle of 40.0o downward. What is its displacement from its starting point?
Q.3. If A = (6.00i – 8.00j) units, B = (-8.00i + 3.00j) units, and C = (26.0i +19.0j) units,
(a)[5] Determine a and b such that aA + bB + C = 0. Remember a and b are scalars.
(b)[5] If D = 3A – 2B then find the magnitude and direction of D. Sketch D.
Q.4..[10] An artillery shell is fired with an initial velocity of 300 m/s at 55.0o above the horizontal. It explodes on a mountainside 42.0 s after firing. What are the x and y coordinates of the shell where it explodes relative to its firing point? (Hint: Do not assume that the shell explodes at its maximum height!)
5.[10] The driver of a car slams on the brakes when he sees a tree blocking the road. The car slows down with uniform acceleration of –5.60 m/s2 for 4.20 s, making straight skid marks 62.4 m long from where he slams on the brakes and up to the tree. With what speed does the car strike the tree?