YOUR NAME. Exam 2 on MAR Physics 105- R. Schad

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1 YOUR NAME Exam on MAR Physics 105- R. Schad

2 1. This is to identify the exam version you have IMPORTANT Mark the A. This is to identify the exam version you have - IMPORTANT Mark the B 3. An object is swirled around with a speed of 5 m/s on a string of 50 cm length. The radial force the string is exerting on the mass is 100 N. IQ What is the mass of the object? [no gravity present] kg b) 10 kg c) 00 kg d) 5000 kg e) None of these 4. If ml would be at 1/ of the distance then the gravity force 1 m exerts on ml [F on 1] would change by a) No change onl b) x 1/ c) x 1 /4 rn 5. The asteroid Eros, one of the many minor planets that orbit the sun in the region between Mars and Jupiter, has a radius of 7.0 km and a mass of 5.0 x 1015 kg and no atmosphere. D What is the velocity with which you would have to fire an object upwards so that it leaves for good [esapes the gravity pull of this astroid]? a) b) d) 5) e) c) Infinite velocity wouod be needed m/s m/s 9.76 m/s None of these. me C) v 6

6. A.0-kg rock is flying with initial y_-velocity v Then a force in the x-direction is acting on it as 4 shown as a function of time. c What is the net [total] velocity at time = seconds?

3 6. A.0-kg rock is flying with initial y_-velocity v Then a force in the x-direction is acting on it as 4 shown as a function of time. c What is the net [total] velocity at time = seconds? 0 A) vnet = -4 B) vnet = C) Vnet = m/ s E) none of these s 6 Ms 7. With a spring-loaded gun fired at an angle of 45deg the projectile will reach a maximum height of 10 m above the start, if the spring had been compressed by 5 cm. How far would you have to compress the spring if you wanted to fire the projectile at the same angle of 45deg to reach a height of 40 m above ground? 10 cm B) 0 cm C) 5 cm D) 15 cm E) None of these 9 oc Iz/<x 8. Two pucks are pushed starting from rest on an air table. Friction is negligible. The puck # has twice the mass of the one that is labeled #1. They are pushed b e ual forces F till the have both the same kinetic ener If #1 reached a speed of I m/s, What is the final speed of #? A) h m/s B) 4 m/s C) m/s D) 1/4 m/s E) I m/s m

4 9. Two pucks are pushed starting from rest on an air table. Friction is negligible. The puck # has twice the mass of the one that is labeled #1. They are pushed by equal forces F till they have both the same momentum. The kinetic energy of #1 and # compare as: a) KEI = KE b) KEI c) KEI = KE d) KEI =4KE P e) KEI = 1/41<E i/ m 10. A wheel rotates about a fixed axis with an initial angular velocity of 0 rad/ s. During a 5 s interval the angular velocity decreases to zero. Assume that the angular acceleration was constant during the 5 s interval. How many revolutions does the wheel turn through during the 5 s interval? a rev b. 50 rev c rev d. 100 rev e. None of these 11. Spaceman Spiff had taken a nap with his spaceship [mtotal = 000 kg] parked in space [zero velocity]. Now he fires the rockets for a 30 s duration to reach a speed of 100 m/ s. The magnitude of the average force of the rockets must have been [mass is assumed to be constant] a kn b kn c kn d kn e. None of these 1. A 0.1 kg object slides down an incline [3 m vertical height] without friction, then continues horizontally across a m long patch with friction and finally hits a spring [spring constant k = 100 N/m]. The object comes to a stop after compressing the spring by 0 cm. The friction coefficient must have been a) 1.5 b) = 0.48 c) g = 0.98 d) g = 0.66 e) None of these

13. Two spring-loaded guns can fire a projectile straight up. They have the same spring constant k. The spring in gun_l is compressed twice as far as the spring of gun_.

5 13. Two spring-loaded guns can fire a projectile straight up. They have the same spring constant k. The spring in gun_l is compressed twice as far as the spring of gun_. The projectiles reach a height of HI and H It must be that: A) Hi = l/4h B) Hi = l/h D) HI =H E) Hi =4H 14. A mass of m = 0 kg started from rest, is moving along the x axis, and is acted upon by a force Fx that varies with position as shown. Which velocity will the mass have reached at x = 8 m? 0 70M 10 tøat« a..65 m/ s b. 3.0 m/ s c m/ s d. 4.0 m/ s e. None of these 15. When the momentum of an object is cut into half [mass unchanged] by what factor is the kinetic energy changed? 1.. 1/ /4 5. None of these

16. Two identical cars, #1 moving with 0 m/ s and # moving with 40 m/ s, slam on the brakes at the same time [same braking force]. #1 stops after 3 seconds. # still moves after 3 sec.

6 16. Two identical cars, #1 moving with 0 m/ s and # moving with 40 m/ s, slam on the brakes at the same time [same braking force]. #1 stops after 3 seconds. # still moves after 3 sec. with how much of its original momentum?? C) 1/4 E) None of these 04b e If a car engine would provide a constant power output for all rpm's [rotational speed] [we stay in the same gear all the time] The torque would 6. 4 'Y ho 1. be constant. decrease linearly with rpm's. 3. increasetinearly with rpm's. 4. decrease quadratically with rpm's. 5. None of these. 18. A space station [mass = 1,000 kg] initially moving with 10 m/s in the +x direction Fires its rockets with a thrust of 1,000 N pushing in the -y direction The magnitude of the final velocity is A) Smaller than the initial speed B) Larger than the initial speed C) The same as the initial speed. D) None of these 19. A solid disc, radius R = m and moment of inertia I = 0 kg m is driven by a motor accelerating it from zero to 5 rad/s in 10 seconds. If the disc were made of a lighter material such that it had twice the radius with the same mass - How long would this take to get to 5 rad/s when accelerated by the same motor? a) IOS c) 0s d) 40 s e) none of these 1

7 0. Two pucks are pushed starting from rest on an air table. Friction is negligible. The puck # has twice the mass of the one that is labeled #1. They are pushed by equal forces F for the same period of time. If #1 gained a speed of I m/s, vahl # C would have which speed? A) 4 m/s ; hoe/ Ire/ C) h m/s D) 1/4 m/s m 1. A car with initial speed of 50 mi/h would brake and skid on a horizontal road coming to a stop just at an obstacle. A car with initial speed of 70 mi/h would hit the brake at the same initial point. It would hit the obstacle with which remaining speed, approximately? a) Zero [would also come to a stop] b) 0 mi / h c) 30 mi / h Dane d) 40 mi / h e) 50 mi / h 3m@v 16. A mass started with an initial velocity of -15 m/s, undergoing accelerations as shown. It wouild reach zero velocity at: a) Os b) 10 s c) 5 s at e) 7.5 s

r r Sample Final questions for PS 150

r r Sample Final questions for PS 150 Sample Final questions for PS 150 1) Which of the following is an accurate statement? A) Rotating a vector about an axis passing through the tip of the vector does not change the vector. B) The magnitude