kallog

Quote:
How long do you think it'll take? Here's a hint. F=3900N, m=100kg, initial speed = 39m/s, F=ma. Any ideas?


if the mass is traveling at a velocity of 39 m/s
and the U turn is 39 meters long , it will take
exactly 1 second.

if the mass is traveling at a velocity of 39 m/s
and the U turn is 19.5 meters long , it will take
exactly 1/2 second.

if the mass is traveling at a velocity of 39 m/s
and the U turn is 9.75 meters long , it will take
exactly 1/4 second.

picture a car on a hill beside a U shaped valley , the car coast down the hill but the car begins to coast up the other hill.

the other hill is the same size and shape of the first hill.

if resistance and friction are zero , the car could coast
up to the top of the other hill.

but will the car need assistance from the hill to coast
up to the other hill?
if so and given that the hill itself will not move and provide a force that would assist the car up the hill
how then can the hill assist the car?

the momentum of the car causes the car to go down the first hill and up the second hill.

the car lost all of its momentum in doing so.

just like the momentum of the mass causes the mass to go half way through the U turn and then through the other half of the U turn.

except the mass has a veocity before it enters the U turn.

now suppose the car was dropped from a
height of 500 ft, the cars momentum would
be enought to send the car down one hill
and up the other hill , and all the way
back up to the altitude it was first dropped from.

Quote:
F=mv is just made up.


nope , its used in hydraulics all the time when describing a fluid pressure that acts against a piston.
there is no time added because the time is itself added

via a=f/m

ie.. apply a force of 10 lb
against a 1 inch hydraulic piston and you get a force
of 100 lb from a opposing 10 sq inch piston.

the F=mv is used to calculate the force that the piston
itself can place on the fluid because of its
mass * velocity.

a lighter piston = less force
a heavier piston = more force

a lighter piston less force required to move the piston itself.
a heavier piston more force required to move the piston itself.

some people work with pistons that weigh several thousand pounds.

thus f=mv


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3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.