A train is traveling south at constant speed 12.0 m/s. Then the brakes are applied & it slows down with a constant acceleration to a speed of 3.00 m/s in a time of 9.00 s. (a) Draw a graph of speed versus time for a 12-s interval (starting 2 s before the brakes are applied and ending 1 s after the brakes are released).
(b) What is the acceleration of the train during the 9.00-s interval?
(c) How far does the train travel during the 9.00 s?

Laboratory experiments, observational field studies, and model-building are all examples of different forms of scientific investigations.  in what way do laboratory experiments primarily differ from other forms of scientific investigations?   a.  a laboratory experiment is the only accepted form of investigation within the scientific community.  b.  studies about how things behave in nature or studies involving very large objects are best answered through laboratory experiments.  c.  laboratory experiments involve the identification and control of variables.  d.  data can only be generated through laboratory experiments, not other forms of investigation.

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

In which of the following cases is work being done on an object? question 2 options: pushing against a locked door carrying a box down a corridor pulling a trailer up a hill suspending a heavy weight with a strong chain