70 g of lead (c=0.031 cal/g.Co) 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 OD QUESTION 2 What is the missing element in the nuclear equation below? 83 210 Bi-->??+_get a) 84/ .210po > b)-205pb - c).219pb . - d).211T galh -> e) none of the above O A OB OC OD m OQUESTION 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 7 If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration a) quadruples b) doubles c) stays the same D) halves e) none of these O A OB OC OD OE QUESTION & What is the resistance of a 120-W incandescent lamp connected to a 120-V power supply? a) 1 ohm b) 60 ohms c) 100 ohms d) 144 ohms e) none of the above OA O B OC OD OE