The angle that the boat must follow for it to be able to head upstream successfully should be 45 degrees from the current at which it is crossing. This is exact protocol that is done or learned by rescuers. In able to swim across a current, you must not invest your energy in heading towards it but rather move in a semi-perpendicular direction from it.
Answer: The illusion of motion that occurs when a stationary object is first seen briefly in one location and, following a short interval, is seen in another location.
Explanation:
question 3 is 3133333.33N/m^2 and question 4 is 4000000N^m2