If Keanu and Zahara are standing at the base of a tall tower and Keanu throws his hat straight upwards, what will Zahara, who is watching Keanu, see happening to the hat as it comes back down? Respond very briefly.
Zahara would see the hat reach a peak height and then start to fall straight back down towards Keanu. This occurs because gravity pulls the hat back towards the Earth after the force of Keanu's throw can no longer sustain its upward motion. The hat would accelerate downwards until Keanu catches it or it hits the ground. The trajectory of the hat would be vertical and could appear to be somewhat parabolic if Keanu's throw imparted any horizontal velocity to it. However, assuming a straight upward throw without any significant wind, Zahara would primarily notice the hat's vertical ascent and descent due to gravity.