A boat, while crossing a river, points directly north toward the opposite shore for the entire trip. the current is perpendicular to the direction the boat is pointing in. the time it will take to cross will be
a. more than if the boat was pointing at an angle somewhat upstream
b. more that if the boat was pointing at an angle somewhat downstream
c. dependent on the strength of the current
d. the same regardless of the current
e. impossible to predict without more information
d. the same regardless of the current.
The direction of the current does not affect the speed at which the boat crosses the river. As long as the boat is pointing directly towards the opposite shore, it will travel in a straight line towards that point. The only factor that affects the time it takes to cross is the speed of the boat relative to the width of the river.