Question

MEDAL GIVEN TO CORRECT ANSWER.
You kick a ball with a speed of 14 m/s at an angle of 51°. How far away does the ball land?

A. 1.8 m
B. 3.96 m
C. 21.3 m
D. 19.6 m

Answer 1

Find the vertical velocity from vsuby = 14 sin (51) = 10.9 m/s

Find how long until the velocity has become zero from
vsuby = 10.9-(9.8) t = 0 due to the negative acceleration of gravity.
t = 10.9/9.8=1.1 sec.

You could calculate the height it reached d then calculate how long it takes to
come back to ground, but the situation is symmetric, so it takes another 1.1 s to fall.

total time is 2.2 s.

Meanwhile, during those 2.2 s, the ball has had a horizontal component of
velocity of vsubx = 14 cos(51= 8.8 m/s
and goes

(8.8 m/s)(2.2s) = 19.4 m .

Looks like D, with a little difference from rounding.