A ball of mass 0.5 kg travelling horizontally through the air with speed v(t) experiences
a drag force DT (t) whose magnitude is given by:
DT (t ) = 0.01[v (t )] 2
The speed of the ball is found to reduce from 10 m/s to 8 m/s over a time interval t,
during which time the ball continues to travel horizontally. Calculate t.
I'm not entirely sure where to start with this. My notes give me the equation for drag forces falling vertically but I wasn't sure what to do because it's travelling horizontally.