00:01
All right, question 67 states that you throw a tennis ball straight upward.
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The initial speed is about 12 meters per second.
00:08
Say everything you can about the motion of the ball.
00:10
Is 12 meters per second a realistic speed for an object that you can throw with your hands? okay, so we're told the initial velocity of the ball is thrown straight up.
00:20
So the first thing i'll do is i'll establish what my positive direction is.
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I'll say in this scenario, my positive direction is upward.
00:28
So that means the ball is thrown with a positive velocity of 12 meters per second.
00:31
Second.
00:33
So what happens when we throw an object straight up, obviously you throw it with some initial speed, it gets to a maximum height, and then begins the fall immediately afterward.
00:42
So if we know v.
00:43
Not, we know the situation at the top such that this velocity is zero.
00:48
So if we look at just this first branch of motion as the ball is going upward, we can represent that motion with the kinematic equation of v squared equals v0 squared.
00:59
Here, if i again, i'm calling my velocity upward to be positive, then my acceleration due to gravity will be negative...