Uphill escape ramps are sometimes provided to the side of steep downhill highways for trucks with overheated brakes. for a simple 11° upward ramp, what minimum length would be needed for a runaway truck traveling 140 km/h? note the large size of your calculated length. (if sand is used for the bed of the ramp, its length can be reduced by a factor of about 2.)

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.)

Acompound machine is also called a machine. a. force b. simple c. complex d. directional

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !