Question

A ball is thrown horizontally at 8m/s. (a) how fast is it moving 2second later? In what direction is it moving?

Answer 1

(a) The horizontal component of the speed remains the same during the entire flight, the vertical component:

$$v_y=gt=9.8·2=19.6\text{ m/s},\\ v=\sqrt{v_y^2+v_x^2}=21.2\text{ m/s}.$$

The direction is

$$\theta=\arctan\frac{v_y}{v_x}=67.8°$$

below the horizontal.