Answer:

Explanation:
As per mechanical energy conservation we can say that here since friction is present in the barrel so we will have
Work done by friction force = Loss in mechanical energy
so we will have

here we know that



Initial compression in the spring is given as



now from above equation




You would know a decomposition reaction occurred if the reactants separated. For example from AB → A+B.
Now if you look at your options only 1 works out for that equation. Letter A.
From the compound K2CO3 it split up to K2O +CO2
It cannot be letter B because synthesis/combination occurred. The same goes for letter C. Letter D, single displacement occurred.
Again, the answer is A.
Answer:
1.35208 m/s
Explanation:
Speed of the boat = 0.75 m/s
Distance between the shores = 100 m
Time = Distance / Speed

Time taken by the boat to get across is 133.33 seconds
Point C is 150 m from B
Speed = Distance / Time

Velocity of the water is 1.125 m/s
From Pythagoras theorem

So, the man's velocity relative to the shore is 1.35208 m/s