At the "very top" of the ball's path, there's a tiny instant when the ball
is changing from "going up" to "going down". At that exact tiny instant,
its vertical speed is zero.
You can't go from "rising" to "falling" without passing through "zero vertical
speed", at least for an instant. It makes sense, and it feels right, but that's
not good enough in real Math. There's a big, serious, important formal law
in Calculus that says it. I think Newton may have been the one to prove it,
and it's named for him.
By the way ... it doesn't matter what the football's launch angle was,
or how hard it was kicked, or what its speed was off the punter's toe,
or how high it went, or what color it is, or who it belongs to, or even
whether it's full to the correct regulation air pressure. Its vertical speed
is still zero at the very top of its path, as it's turning around and starting
to fall.
Answer:
A= 150 J
Explanation:
Kinetic energy is the energy of an object in motion.
The formula for kinetic energy is ;
K.E = 1/2 * m *v² where m is mass and v is velocity
Work done is equal to change in kinetic energy
W= Δ K.E
Given that K.E = 150 J
Taking that the ball was stationary before it was thrown, this makes its initial kinetic energy to be 0 J so the work done will be
W= Δ K.E
W= 150 - 0
W= 150 J
Answer:
Normal force=mg
Explanation:
The reaction force of weight is the normal force.
in order to find the normal for we need to write all the forces and set it equal to the net force:
N-mg=ma (since it is a constant speed the a=0)
N=mg
OK. Thank you. That's an impulse of 200 Newton-sec to the left,
telling us that the cart's leftward momentum increases by 200 kg-m/s
(or its rightward momentum decreases by that amount).
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