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2 answers:
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The final velocity is 1.37 m/s east
Explanation:
We can solve this problem by using the law of conservation of momentum: in fact, in absence of external forces, the total momentum of the two trains must be conserved before and after the collision.
So we can write:
where:
is the mass of the first train
is the initial velocity of the first train (we take east as positive direction)
is the mass of the second train
is the initial velocity of the second train
is the final combined velocity of the two trains
Re-arranging the equation and substituting the values, we find:
And the positive sign indicates their final direction is east.
Learn more about momentum here:
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Answer:
8100W
Explanation:
Let g = 10m/s2
As water is falling from 60m high, its potential energy from 60m high would convert to power. So the rate of change in potential energy is
or 9000W
Since 10% of this is lost to friction, we take the remaining 90 %
P = 9000*90% = 8100 W