Answer:
(OD) Velocity
Explanation:
Here, the rider is moving with a steady speed (5 m/s) towards south. In this example, we have magnitude as well as direction. Since velocity is a vector quantity, thus we can determine the velocity of the rider.
Take the derivative to find the velocity of the object:
The object stops when 
:
so the answer is E.
"Three short blasts" sound signal alerts others when a boat is backing up based on the boating safety rule. The short blast is a sound which has one second period, thus three short blasts mean three of this kind of sound. The sound signal is used for alerting anything surrounding the boat to avoid a collision.
Inertia is what keeps everything moving, so if it didn't exist, the balls wouldn't keep going when they are kicked, or thrown.
