A motorboat starting from rest travels in a straight line on a lake.(a)If the boat achieves a speed of 7.00 m/s in 15.0 s, what is the boat's average acceleration?magnitude in ____m/s2 What direction? opposite to the direction in motion or in the direction of motion? (b)If the boat continues with the same acceleration, what would be its speed after another 6.00 s? in ____m/s