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A ship has two engines, one producing a ...

A ship has two engines, one producing a thrust of 300 newtons and the other 750 newtons . Firing the smaller engine for 10s speeds the ship up from 80 metres per second to 95 meters per second, and the large engine is then fired for 12 seconds. How fast is the ship then going.

Text Solution

Verified by Experts

The two impulses are
impulse 1 `=f Delta t= (300N) times (10s)=3000 Ns`
Impulse 2 `=f Delta t=(750 N) times (12s)=9000Ns`
So the second impulse must produce three times as much change in velocity as the first. The first change was `95m//s -80m//s =15m//s` so the second impulse increases the velocity by 45 metres per second , from 95 meters per second to 140 meters per second.
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Knowledge Check

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