70 g of lead (c=0.031 cal/g.C") is added to 100 g of water (c = 1 cal/g.C ) initially at 30"C. If the final temperature of the system is 50"C, what was the initial temperature of the lead? a) 80"C b) 972" C () 311' C d) 70" C OA OB OC ODQUESTION 3 In which case is zero work done? a) The work done by Earth on a ball as the ball, which was initially at rest, falls 3.0 m down towards Earth. b) A eastward force is applied to an eastward moving soccer ball that is already moving at a constant velocity to increase its speed in that direction. c) A cart is moving at a constant velocity of 10 m/s [W] when a 0.5 N [downward] force is applied d) The work done by Earth on an arrow as it is fired 200 m straight up into the air. e) A cart is moving at constant velocity of 10 m/s [W], when 0.5 N (westward) force is applied OA OB OC OD OE QUESTION 4 In an elastic collision of two bodies of equal masses a) velocities of two bodies are zero after collision b) velocities of both bodies decrease after collision c) velocities of two bodies remain unchanged after collision d) velocities of two bodies are exchanged after collision e) velocities of both bodies increase after collisionQUESTION 5 Displacement is a. The same as the distance b. Depends on the path traveled c. independent of the path traveled d. requires both magnitude and direction e. both a and b are true f. both c and d are true O A O B OC OD OE OF QUESTION 6 The normal force in friction considerations a. is the same as the force of friction b. is always equal to the weight of the object c. may be equal to or greater than the weight of the object d. may be equal to or less than the weight of the object e. may be equal to, less than or greater than the weight of the objectQUESTION 10 The current through two identical light bulbs connected in series is 0.25 A. The voltage across both bulbs is 110 V. The resistance of a single light bulb is a) 22 ohms b) 44 ohms c) 220 ohms d) 440 ohms. e) none of the above OA OB OC OD OEQUESTION 12 An object is 2 m in front of a plane mirror. Its image is a. Virtual, inverted, and 2 m behind the mirror b. Virtual, inverted, and 2 m in front of the mirror c. Virtual, upright, and 2 m in front of the mirror d. Virtual, upright, and 2 m behind the mirror e. none of the above O A O B OC OD OEQUESTION 14 Fig.46 shows the passage of a ray of light from air (n =1) into a substance X. The index of refraction of X is: a) 0.53 b) 0.88 c) 1.9 d) 2.2 e) 3.0 40 Air Fig.461 709 X1 O A O OC OD OEWhen Danny Diver who weighs 500 N steps off a diving board 10 m above the water, he hits the water with a velocity of in m/'s A) 4.5 B) 14 C) 20 D) 200 E) none of these O A O B OC OD OEQUESTION 22 A change of 100" on the Celsius scale is equal to a change of how many degrees on the Fahrenheit scale? a) 100 b) 120 c) 180 d) 212 e) 55.5 O A O B OC OD OE QUESTION 23 When we consider the distance a pendulum swings to and fro we're talking about the pendulum's a) frequency b) Twice the amplitude c) wavelength d) amplitude e) period O A O B OC OD OE QUESTION 24 How much heat must be removed from 100 g of steam at 100 *C to create water at 20 "C? (Hy=540 cal/g, Cw=1 cal/g.C", HF=80 cal/g.) a) 62000 cal b) 8000 cal () 54000 cal d) 16000 cal e) need the specific heat capacity of steam