41. At what angle (relative to the horizontal) should a : 2102141
41. At what angle (relative to the horizontal) should a curve 52 m in radius be banked if no friction is required to prevent the car from slipping when traveling at 12 m/s? (g = 9.8 m/s2)
42. At what speed will a car round a 52-m-radius curve, banked at a 45? angle, if no friction is required between the road and tires to prevent the car from slipping? (g = 9.8 m/s2)
A. 27 m/s
B. 17 m/s
C. 23 m/s
D. 35 m/s
43. A roller coaster, loaded with passengers, has a mass of 2 000 kg; the radius of curvature of the track at the bottom point of the dip is 24 m. If the vehicle has a speed of 18 m/s at this point, what force is exerted on the vehicle by the track? (g = 9.8 m/s2)
A. 2.3 ´ 104 N
B. 4.7 ´ 104 N
C. 3.0 ´ 104 N
D. 1.0 ´ 104 N
44. Consider a point on a bicycle tire that is momentarily in contact with the ground as the bicycle rolls across the ground with constant speed. The direction for the acceleration for this point at that moment is:
B. down toward the ground.
D. at that moment the acceleration is zero.
45. Consider a child who is swinging. As she reaches the lowest point in her swing:
A. the tension in the rope is equal to her weight.
B. the tension in the rope is equal to her mass times her acceleration.
C. her acceleration is downward at 9.8 m/s2.
D. none of the above.