Answer:
a

b
Explanation:
From the question we are told that
The velocity of the river due east is 
The velocity of the boat due north is 
The width of the river is 
Generally the velocity of the boat relative to the shore

=> 
=> 
Generally direction of the boat relative to the shore is mathematically represented as

=> ![\theta = tan^{-1}[ \frac{v}{v_1}]](https://tex.z-dn.net/?f=%5Ctheta%20%20%3D%20tan%5E%7B-1%7D%5B%20%5Cfrac%7Bv%7D%7Bv_1%7D%5D)
=> ![\theta = tan^{-1}[ \frac{1.5}{10}]](https://tex.z-dn.net/?f=%5Ctheta%20%20%3D%20tan%5E%7B-1%7D%5B%20%5Cfrac%7B1.5%7D%7B10%7D%5D)
=> 
Generally the distance covered by the boat in the direction of flow of the river before reaching the north shore is mathematically represented as

=> 
=>
<span>2Kg50m/
s2.5m/
s2<span>2m/
s2</span></span>
by the wind and air flow in the wind
Answer:
speed of molecule ∝ 1/mass of molecule.
Explanation:
The velocities of the molecules depend on their masses. That's because if the molecules are large in size, their velocity is slower. Therefore their velocity is quicker when their size is small, since the molecules can move faster.
Therefore , it can be written as
speed of molecule ∝ 1/mass of molecule.