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an object is thrown horizontally off a cliff with an initial velocity of 5.0 meters per second. the object strikes the ground 3.0
seconds later. what is the horizontal speed of the object 1.0 second after it is released? neglect friction.
1 5.0 m/s
2 10. m/s
3 15 m/s
4 30. m/s

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

Jackson is designing a new heater, and he wants to experiment with different thermally conductive materials. which of these materials would be useful in conducting heat?

Aballet student who learns with the of his instructor is demonstrating learning.