Ages of Amtrak Passenger CarsThe average age of Amtrak

College Physics 1
Problem 16PE A brave but inadequate rugby player is being pushed backward by an opposing player who is exerting a force of 800 N on him. The mass of the losing player plus equipment is 90.0 kg, and he is accelerating at 1.20 m/s2 backward. (a) What is the force of friction between the losing player

Fundamentals of Physics: 9
A rope of negligible mass is stretched horizontally between two supports that are 3.44 Fig. 12-24 Problem 3. m apart. When an object of weight 3160 N is hung at the center of the rope, the rope is observed to sag by 35.0 cm. What is the tension in the rope?

Conceptual Physics 12
Find the change in the force of gravity between two planets when the distance between them becomes 10 times smaller.

Psychology 5
What is the process by which people come to understand others? a. social influence b. reciprocal altruism c. social cognition d. cognitive dissonance

Biology for AP Courses
Which of the following are two examples of vestigial structures? a. gills in fish and parts of the throat in humans b. butterfly wings and dragonfly wings c. hind leg bones in whales and leaves on some cacti d. shark fins and dolphin fins

Essentials of Understanding Psychology 11
Who pioneered the study of conformity? a. Skinner b. Asch c. Milgram d. Fiala

Urban Economics 8
Distance between Bus Stops Consider a city that decreases the distances between bus stops, which decreases the walking time of bus riders by 20 percent, increases the in-vehicle (line-haul) time by 10 percent, and increases operating cost by 10 percent. On the typical bus line, the initial ridership

Principles of Economics 9
Which of the following does NOT add to U.S. GDP? a. Boeing manufactures and sells a plane to Air France. b. General Motors builds a new auto factory in North Carolina. c. The city of New York pays a salary to a policeman. d. The federal government sends a Social Security check to your grandmother.