The time taken by the swimmer was 1 hour.
Why?
Since the swimmer is maintaining an angle of 150° while he was swimming, there were two components of the speed (horizontal and vertical). If we want to calculate the time taken by him to cross the river, we need to calculate the vertical speed and consider that the flow's speed is compensated by his horizontal speed.
We can calculate both components of the speed using the following formula:

Now, calculating we have:

Therefore, we have that the horizontal speed is compesating the flow's speed while his vertical speed is used to cross the river which is 1 Km wide.
Hence, we have that the tame taken is:

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Answer:
no
Explanation:
the inertia of an object does not make it to come to rest, this is normally caused by friction
Answer:
No.
Explanation:
Acceleration of an object is defined as the rate of change of velocity per unit time. It can be given by :
a = dv/dt
dv is the change in velocity i.e. final velocity-initial velocity
dt is change in time
At a particular time, its change in velocity can be one only. It would imply that a body cannot have two acceleration at a particular time.