Re: How does drill variable speed work?
Posted: Wed Feb 22, 2006 12:49 pm
Hello again,
Chris:
Gravity, a force in itself, does not affect the speed because its
direction is 90 degrees away from the line of movement. It's the
effect of gravity on the friction in the bearings and where the tires
meet the road surface...both are friction... which i thought we
agreed to ignore. We're also ignoring relativistic effects because
our experiment is running much, much slower than the speed of light.
Once we agree on these things we can move to include friction or
whatever if you like...agreed? If you dont like this then we'll use
rockets in deep space (as you suggested) with no air friction and
no gravity (far away from other objects).
Here's a simpler analogy from the basic laws of motion...
Starting with
F=M*A
we get
F=M*dv/dt
F*t=M*V
V=t*F/M+V0
V=t*F/M (setting V0=0)
From this we can prove that:
Twice the mass of M accelerates to velocity V in twice the time
mass M does (assuming constant acceleration and V0=0 for both)...
V1=t1*F/(M)
V2=t2*F/(2*M), where t2=2*t1 (twice the time, twice the mass)
then
V1=V2
So both masses get to the same speed only at different times.
If we stop applying force to mass 1 after time t1 once mass
2 gets to time t2 (twice t1) both masses will be traveling
at the same speed. If we then stop applying force to mass 2
as well then both masses will continue to travel at the same
speed forever.
Take care,
Al
Chris:
Gravity, a force in itself, does not affect the speed because its
direction is 90 degrees away from the line of movement. It's the
effect of gravity on the friction in the bearings and where the tires
meet the road surface...both are friction... which i thought we
agreed to ignore. We're also ignoring relativistic effects because
our experiment is running much, much slower than the speed of light.
Once we agree on these things we can move to include friction or
whatever if you like...agreed? If you dont like this then we'll use
rockets in deep space (as you suggested) with no air friction and
no gravity (far away from other objects).
Here's a simpler analogy from the basic laws of motion...
Starting with
F=M*A
we get
F=M*dv/dt
F*t=M*V
V=t*F/M+V0
V=t*F/M (setting V0=0)
From this we can prove that:
Twice the mass of M accelerates to velocity V in twice the time
mass M does (assuming constant acceleration and V0=0 for both)...
V1=t1*F/(M)
V2=t2*F/(2*M), where t2=2*t1 (twice the time, twice the mass)
then
V1=V2
So both masses get to the same speed only at different times.
If we stop applying force to mass 1 after time t1 once mass
2 gets to time t2 (twice t1) both masses will be traveling
at the same speed. If we then stop applying force to mass 2
as well then both masses will continue to travel at the same
speed forever.
Take care,
Al