If the boat is floating, then it's just sitting there, and not accelerating
up or down. That means the vertical forces on it must be balanced.
So if its weight (acting downward) is 100 newtons, then the buoyant
force on it (acting upward) must also be 100 newtons.
The electrical force between these two charges remains the
same. In coulomb’s law, it states that the magnitude of two charges (product of
two charges) is inversely proportional to the square of the distance. Since both
the magnitude and the distance are halved, therefore, the change in both quantities
will have no effect in the value of electrical force.
(a) The magnitude of the wind as it is measured on the boat will be the result of the two vectors. Since they are at 90°, the resultant can be determined by the Pythagorean theorem.
R = sqrt ((20 knots)² + (17 knots)²)
R = sqrt (400 + 289)
R = 26.24 knots
The direction of the wind will have to be angle between the boat and the resultant.
cos θ = (20 knots)/(26.24 knots)
θ = 40.36°
Hence, the direction is 40.36° east of north.
(b) As stated, the wind is blowing in the direction that is to the east. This means that it only has one direction. Parallel to the motion of the boat, the magnitude of the wind velocity will have to be zero.
