A man weighing 70 kg runs alongside railroad tracks with a velocity of 18 km/h, and jumps into a car of weight 100 kg standing on the tracks.
Calculate the velocity with which the car and man will start moving.

Mass of man (m1) = 60kg            

Initial velocity of man (u1) = 18 km/h=18x5/18=5m/s

Final velocity of man (v1) = (v2) = v  

Mass of car (m2)= 100kg

Initial velocity of car (u2) = 0 (as it is in rest)

Final velocity of car (v2) = v

According to law of conservation of momentum,

m1u1 +m2u2 = m1v1 + m2v2

60x5 + 100x0 = 60 x v + 100 x v

300+0 = 160v  

v = 300/160

v = 1.875 m/s

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answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.