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:

Have a nice day!
Answer:
TEMPERATURE
Explanation:
When a wave is absorbed by a material medium, different phenomena occur, but the collisions with the other particles causes the energy to be transformed into internal energy in the atoms and molecules of the material, with TEMPERATURE measurements the increase in the internal energy of the material.
Air that is not saturated will cool or heat at a rate of 10 degrees C/1000 meters as it rises or descends, respectively
The rate of the change in temperature which is observed while moving upward in the earth's atmosphere with elevation. It can be positive, negative and zero when the temperature decreases, increases or is constant with the elevation respectively.
For the atmosphere, the drop in temperature of rising air that is unsaturated air is about 10 degrees C/1000 meters (5.5 °F per 1000 feet) altitude.
That means if a there occur a rise of 1000 m , then the temperature of that thing will decrease to 10 degrees. Every 10°C of temperature from the given temperature will decrease at every rise of 1000 m .Air that is not saturated will cool or heat at a rate of 10 degrees C/1000 meters as it rises or descends, respectively
To learn more about unsaturated air here
brainly.com/question/13434971?referrer=searchResults
#SPJ4
On the mass subject you could simply change the weight, on the texture subject you could smooth it out like polishing fresh wood, or you could change the color of water with a drink-mix packet. Hope it helped!