During a storm, a car traveling on a level horizontal road comes upon a bridge that has washed out. The driver must get to the other side, so he decides to try leap- ing the river with his car. The side of the road the car is on is 21.3 m above the river, while the opposite side is only 1.8 m above the river. The river itself is a raging torrent 48.0 m wide. (a) How fast should the car be traveling at the time it leaves the road in order just to clear the river and land safely on the opposite side

Explanation:

Distance of fall = 21.3 - 1.8 = 19.5 m

horizontal distance covered = 48 m

Let  horizontal speed of car required = u

Time to reach the other side

=  48 / u

This time is required for vertical fall

h = 1/2 g t²

19.5 = 1/2 g ( 48/u)²

u² = 579

u = 24 m /s

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-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

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