7.a railway truck A of a mass of 2000kg moves westwards with a velocity of 3m/s. It collides with a stationary truck B 1200kg, loaded with electronic equipment of mass 300kg. The two trucks combined after collision. Ignore the effects of friction. 7.1. Write down magnitude and direction of the 'reaction force' to the weight of truck A.
(2)
7.2. Calculate the velocity of truck B after the collision.
(5)
7.3. Calculate the magnitude of the force that the truck A exert on truck B if
the collision lasts for 0,5 s.
(4)
8. The most common reasons for rear-end collisions are too shortfollowing a
distance, speeding and failing brakes. The sketch below represents one such​

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.

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