What causes the acceleration to increase or decrease?

A freight car moves along a friction less level railroad track at constant speed. The car is open on top. A large load of coal is suddenly dumped into the car. What happens to the velocity of the car?

A piano tuner strikes a tuning fork at the same time he strikes a piano key with a note of a similar pitch. If he hears 3 beats per second, and the tuning fork produces a standard 440 Hz tone.

A kiddie roller coaster car has a mass 100 kilograms. At the top of a hill, it's moving at a speed of 3 meters/second. After reaching the bottom of the hill, its speed doubles. The car's kinetic energy at the bottom is its kinetic energy at the top.

A steel pipe of 12-in. outer diameter is fabricated from 1 4 - in.-thick plate by welding along a helix that forms an angle of 25° with a plane perpendicular to the axis of the pipe.

geography Which nation in the region has seen its growth rate accelerate, while the majority of the region has seen a decline in growth rates?

What is the fundamental unit for measuring mass in the metric system?

Why are some craters on the moon bigger than others

What object oriented feature can we use to have a single test program, with one set of method calls in which the user can decide which bag implementation (array - or link-based) needs testing?

What might motivate someone to study forensics

A roller coaster at an amusement park has a dip that bottoms out in a vertical circle of radius r. A passenger feels the seat of the car pushing upward on her with a force equal to five times her weight as she goes through the dip. If r = 17.