Aball is thrown horizontally from a cliff at 8m/s .in what direction is the ball moving 2s later?

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: