B) x1– x2 C) + x1 x2 D) x1 E) x2 Ans: A. Difficulty: Easy Section 2-1 Learning objective 2.1.3 5. A car starts from Hither, goes 50 km in a straight line to Yon, immediately around, and returns to Hither. The time for this round trip is 2 hours. The magnitude of the average velocity of the car for this round trip is: A) 0 km/hr B) 50 km/hr C) 100 km/hr D) 200 km/hr E) cannot be calculated without knowing the acceleration Ans: A Difficulty: Easy Section: 2-1 Learning Objective 2.1.4 6. The coordinate of an object is as a function of time by = 7t 3t2, where is in meters x x – and is in seconds. Its average velocity over the interval from = 0 to = 2 s is: t t t A) 5 m/s B) m/s –5 C) 11 m/s D) m/s –11 E) 1 m/s Ans: E Difficulty: Medium Section: 2-1 Learning Objective 2.1.4 7. The position of a particle moving along the axis depends on the time according to the y y t equation = The dimensions of the quantities and are respectively: y at bt2. a b – A) L2/T, L3/T2 B) L/T2, L2/T C) L/T, L/T2 D) L3/T, T2/L E) none of these Ans: C
B) x1– x2 C) x1 + x2 D) x1 E) x2 Ans: A. Difficulty: Easy Section 2-1 Learning objective 2.1.3 5. A car starts from Hither, goes 50 km in a straight line to Yon, immediately around, and returns to Hither. The time for this round trip is 2 hours. The magnitude of the average velocity of the car for this round trip is: A) 0 km/hr B) 50 km/hr C) 100 km/hr D) 200 km/hr E) cannot be calculated without knowing the acceleration Ans: A Difficulty: Easy Section: 2-1 Learning Objective 2.1.4 6. The coordinate of an object is as a function of time by x = 7t – 3t2, where x is in meters and t is in seconds. Its average velocity over the interval from t = 0 to t = 2 s is: A) 5 m/s B) –5 m/s C) 11 m/s D) –11 m/s E) 1 m/s Ans: E Difficulty: Medium Section: 2-1 Learning Objective 2.1.4 7. The position y of a particle moving along the y axis depends on the time t according to the equation y = at – bt2. The dimensions of the quantities a and b are respectively: A) L2/T, L3/T2 B) L/T2, L2/T C) L/T, L/T2 D) L3/T, T2/L E) none of these Ans: C