A ball is thrown horizontally at a speed of 24 meters per second from the top of a cliff. If the ball hits the ground 4.0 seconds later, approximately how high is the cliff? I NEED HELP FOR THIS QUIZ LOL

78.4m

Explanation:

In these situations, vertical and horizontal components need to be considered separately;

So, horizontal speed is irrelevant since we are talking about vertical height, i.e. the height of the cliff;

But, the fact that the speed is horizontal is relevant because this means the vertical speed initially is 0m/s;

The downwards movement of the ball is due to gravity, which is 9.8m/s²;

The time is given as 4.0s from the top of the cliff to the bottom;

We know the acceleration, time and initial speed so we can use this kinematic equation to solve for distance:

s = ut + ¹/₂at²

s = displacement (/distance)

u = initial vertical velocity = 0

t = time (time taken for the ball to fall) = 4

a = acceleration (downwards) = 9.8

Substitute these values into the equation to get the distance:

s = 0(4) + ¹/₂(9.8)(4)²

s = 78.4m

fgravity=10x10=100n case 1

fgravity=30x20=600n case 2

6 times more

no. dot product   =0 when vecs at right angles