Answer:
120 km/h
Explanation:
This is a case of a parabolic motion. For this kind of motion the horizontal component of the velocity does not change in the complete trajectory. That is:

Then, the velocity of the ball at the moment in which the catcher caught the ball is:

the velocity of the ball is 120 km/h.
Answer:
x(t) = -8sin2t
Explanation:
See the attachment for solution
From my solving, we can deduce that w² = 4, and thus, w = 2
Therefore, the general solution is
x(t) = c1 cos2t + c2 sin2t
Considering the final variable, we can conclude that
x(0) = 0
x'(0) = -8 m/s
The final solution, thus
x(t) = -8sin2t
Answer:
B
Explanation:
Reason is that the suitcase is exerted downward and when it moves downward the equation is mgsin tita