PHY101_Exam1example

PHY101_Exam1example - PHY 101 Student Name: PRINT EXAM...

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Unformatted text preview: PHY 101 Student Name: PRINT EXAM 1-Example 2008 Last:_______________________First:__________________ ID# ___________ Signature___________ Recitation Section #: ____________________ You are allowed a calculator and ONE 8.5"x11" sheet of paper with whatever you wish written on it (both sides). You must show ALL your work to receive full credit for regular problems. Numerical answers must have the right units. Use the back of the problem page if you need more space and mark OVER on the front to indicate that there is material on the back side. Clearly circle the letter of your choice for the multiple choice problems. No points will be given if two or more choices are circled. Maximum marks: 100, Time: 2 hours Please note that giving or receiving aid on an exam or any act of academic dishonesty is cause for dismissal from the University. Question 1-8 9 10 11 12 Score Grader _____ _____ _______ _______ Constants that may be useful: g = 9.8 m/s2 ; Student Name:___________________________Student Number:_________ MultipleChoiceQuestions Clearly circle the letter of your choice, you do not need to show your work. No points will be given to questions with two or more choices marked. No partial credit will be given. 1. If the displacement of an object, x, is related to velocity, v, according to the relation x = Av, the constant, A, has the dimension of which of the following? (3 points) (a) acceleration (b) length (c) time (d) area 2. A high fountain of water is in the center of a circular pool of water. You walk the circumference of the pool and measure it to be 150 meters. You then stand at the edge of the pool and use a protractor to gauge the angle of elevation of the top of the fountain to be 55. How high is the fountain? (3 points) (a) 17 m (b) 23 m (c) 29 m (d) 34 m 3. In which one of the following situations does the car have a westward acceleration? (3 points) (a) The car travels westward at constant speed. (b) The car travels eastward and speeds up. (c) The car travels westward and slows down. (d) The car travels eastward and slows down. (e) The car starts from rest and moves toward the east. 4. A rock is thrown vertically upward from the surface of the earth. The rock rises to some maximum height and falls back toward the surface of the earth. Which one of the following statements concerning this situation is true if air resistance is neglected? (3 points) (a) As the ball rises, its acceleration vector points upward. (b) The ball is a freely falling body for the duration of its flight. (c) The acceleration of the ball is zero when the ball is at its highest point. (d) The speed of the ball is negative while the ball goes up from the earth. 5. An eagle is flying due east at 8.9 m/s carrying a mouse in its legs. The mouse manages to break free at a height of 12 m. What is the magnitude of the mouse's velocity as it reaches the ground? Note: effects of air resistance are not included in this calculation. (3 points) (a) 22 m/s (b) 11 m/s (c) 8.9 m/s (d) 18 m/s (e) 9.8 m/s 6. A tennis ball is thrown upward at an angle from point A. It follows a parabolic trajectory and hits the ground at point D. At the instant shown, the ball is at point B. Point C represents the highest position of the ball above the ground. C B A D While in flight, how do the x and y components of the velocity vector of the ball compare at the points B and C? (3 points) (a) The velocity components are non-zero at B and zero at C. (b) The x components are the same; the y component at C is zero m/s. (c) The x components are the same; the y component has a larger magnitude at C than at B. (d) The x component is larger at C than at B; the y component at B points up while at C, it points downward. (e) The x component is larger at B than at C; the y component at B points down while at C, it points upward. 7. A baseball batter hits an incoming 40-m/s fastball. The ball leaves the bat, in the opposite direction, at 50 m/s after a ball-on-bat contact time of 0.030 s. What is the force exerted on the 0.15-kg baseball? (3 points) (a) 450 N (b) 250 N (c) 90 N (d) 50 N 8. In a tug-of-war, each man on a 5-man team pulls with an average force of 500 N. What is the tension in the center of the rope? (3 points) (a) zero N (c) 500 N (e) 5000 N (b) 100 N (d) 2500 N Student Name:___________________________Student Number:_________ Problems: You MUST show ALL your work and use correct units for numerical answers to receive full credit! 9A. A chimpanzee sitting against his favorite tree suddenly gets up and walks 51 m due east and then 39 m due south to reach a termite mound, where he eats lunch. (a) What is the shortest distance between the tree and termite mound? (6 points) (b) What angle does the shortest distance make with respect to due east? (6 points) 9B. An observer, whose eyes are 1.83 m above the ground, is standing 32 m away from a tree. The ground is level, and the tree is growing perpendicular to it. The observer's line of sight with the treetop makes an angle of 20o above the horizontal. How tall is the tree? (7 points) Student Name:___________________________Student Number:_________ 10. A car travels along a straight path in three segments as follows: Segment 1: Start from rest with a constant acceleration of 2.77 m/s2 for 15.0 s Segment 2: Maintain a constant velocity for the next 2.05 min Segment 3: Apply a constant negative acceleration of -9.47 m/s2 for 4.39 s (a) What is the value of the constant velocity in the second segment? (3 points) (b) What is the total displacement for the trip? (4 points) (c) What are the average speeds for segments 1, 2 and 3 of the trip? (3 x 3 = 9 points) (d) What is the average speed for the entire trip? (3 points) Student Name:___________________________Student Number:_________ 11. A rescue airplane moving horizontally with a constant velocity of +115 m/s at an altitude of 1050 m, releases a food package to pilots stranded in an island. Ignore air resistance. (a) What are the magnitude and direction of the horizontal and vertical components of acceleration of the food package? (1+1+1+1 = 4 points) (b) What is the time required for the package to hit the ground? (4 points) (c) What are the horizontal and vertical components of the velocity when the package hits the ground? (2+4= 6 points) (d) What is the total final velocity? (2 points) (e) What is the angle of the final velocity vector of the package when it strikes the ground? (3 points) Student Name:___________________________Student Number:_________ 12. A car of mass m = 2000 kg is on an icy driveway inclined at = 20 o, as in figure. Assume that the incline is frictionless. (a) Draw a free body diagram indicating all the forces involved (2 points) (b) Find the acceleration of the car (5 points) (c) If the length of the driveway is 25 m and the car starts from rest, how long does it take to travel to the bottom? (5 points) (d) What is the speed of the car at the bottom? (5 points) (e) If the car's mass is changed to 5000 kg, what will be new the accelaration? (2 points) ...
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This note was uploaded on 10/02/2008 for the course PHY 101 taught by Professor Pralle during the Fall '08 term at SUNY Buffalo.

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