A football kicked with speed $u = 20$ m/s at $30^\circ$ above horizontal has initial vertical component approximately:
A$20$ m/s upward, equal to the full launch speed of the ball
B$10$ m/s upward, since $u\sin 30^\circ = 20\cdot 0.5$
C$17.3$ m/s upward, since vertical is the longer leg here
DZero, because vertical speed is always zero at start
Answer & Solution
Correct answer: B. $10$ m/s upward, since $u\sin 30^\circ = 20\cdot 0.5$
$u_y = u\sin\theta = 20\cdot \sin 30^\circ = 20\cdot 0.5 = 10$ m/s.