Answer:
67.8 degrees below horizontal
Explanation:
In order to understand the direction of the ball after a certain time t, we need to find its horizontal and vertical components of the velocity.
- Horizontal component: the horizontal component of the velocity of the ball is constant, since there are no forces acting along this direction. Therefore, its horizontal velocity after t = 2 s is
vx = 8 m/s
- Vertical component: the vertical component of the velocity of the ball is given by
vy = u + at
where
u = 0 is the initial vertical velocity
a = g = -9.8 m/s^2 is the acceleration of gravity
Substituting t = 2s,
vy = 0 + (-9.8 m/s^2)(2s )=-19.6 m/s
where the negative sign indicates it points downward.
So, the direction of the ball (given as angle below the horizontal) is:
[tex]\theta = tan^{-1} (\frac{|v_y|}{v_x})=tan^{-1} (\frac{19.6 m/s}{8 m/s})=67.8^{\circ}[/tex]
