What’s the velocity of a ball falling with 100 joules of kinetic energy and a mass of 2 kilograms? use the formula, . 3 m/s 5 m/s 7 m/s 8 m/s 10 m/s

Kinetic energy of freely falling ball = 
∴ velocity of ball = √(2×K.E/m) = √(200/2) = 10 m/s.

The boat's velocity relative to the riverbank can be resolved into two components. the component going north is 2.7 m/s and the component going west is 1.2 m/s.we add these two vectors and then find the magnitude of the resultant to get the speed.the magnitude of the resultant vector from adding can be obtained by the pythagorean theorem.    to two significant figures, the boat's speed relative to the riverbank is 3.0 m/s.