7.) What rapidly expanding Midwestern city served as the most important railroad hub, connecting the Eastern seaboard and the West during the late 19th century?

What is the main difference between paid and unpaid search traffic?

Suppose you walk 30 meters east, 10 meters north, then 6 meters west.  How far are you from your initial position?

An object’s velocity as a function of time is v(t) = 12 – 4t.  At what time does the object change direction?

A ball is thrown into the air with some initial velocity.  It rises to a maximum height, turns around and falls to the Earth.  Which statement describes the acceleration vector during this motion?  Assume a coordinate system where up is positive.

A 400 kg roller coaster travels at 10 m/s over the top of a track (point B).  If the track at point B is part of a circle with radius r2 = 20 m, what is the normal force acting on the cart?

A block starts with some initial velocity and travels up a ramp as shown. Which of the following diagrams correctly shows the forces on the block? image00455ff9ad255ff9ad2.gif

A block slides on a horizontal table.  If the coefficient of kinetic friction between the table and the block is 0.3, what is the acceleration?  You should find that mass cancels out when you apply Newton’s 2nd law.

A coffee filter is dropped from rest and reaches a terminal velocity of 1 m/s.  The cross section area of the filter is .017 m2 and it has a mass of 0.00084 kg.  What is the drag coefficient of the filter?  The density of air is 1.2 kg/m3.  The drag force is proportional to v2.

Suppose an object’s velocity vector points to the right and its acceleration vector points left.  What can you say about its motion?