A ferry can travel at an optimal speed of 8 km/h in still water measured relative to the shore. What is the optimal speed of the ferry, relative to the shore, if it moves perpendicular to a 6 km/h current?
A 4 km/h
B 8 km/h
C 10 km/h
D 14 km/h
E 28 km/h
A baseball is hit upward and travels along a parabolic arc before it strikes the ground. Which one of the following statements is necessarily true?
A The acceleration of the ball decreases as the ball moves upward.
B The velocity of the ball is zero m/s when the ball is at the highest point in the arc.
C The acceleration of the ball is zero m/s2 when the ball is at the highest point in the arc.
D The x-component of the velocity of the ball is the same throughout the ball's flight.
E The velocity of the ball is a maximum when the ball is at the highest point in the arc.
Two question: one pertaining to the optimal speed of a ferry along a shore and the other is to do with the parabolic curve of a baseball hit upwards.