F=MxA

[opds9091]

i overheard a bunch of guys talking about there bikes and a whole bunch of things. They were talking about
FORCE EQUALS MASS TIMES ACCELARTION.....(F= MxA)
What the hell does that mean?

 

[wrightme43]

This may help some

accident reconstruction,engineering physics,speeds,distance,energy


I am not a good teacher and it is hard for me to explain.

Acceleration is change in direction over time.

See if this makes sense

Its really all about time.

Stopping a 200 kilo bike and rider in .1 of second
vs
Stopping a 200 kilo bike and rider in 3.1 seconds would do to drasticly different things with force.

Does that help?

 

[Mattberkshire]

Dunno but Distance Equals Rate Times Time is a great song

 

[xj750_Pete]

That's just an equation for force. Basically a force is anything that has mass and is accelerating. For example when you push someone you are exerting a certain amount of force by accelerating their mass.

 

[opds9091]

OK, now I'm really confused. I understood a little bit about the velocity and falling idea, but i will shut up about it and ride on.

 

[opds9091]

so you mean.....anything that can move will move and when motion is forced that what velocity is.........

 

[greenthumb]

so you mean.....anything that can move will move and when motion is forced that what velocity is.........

no,
velocity is speed and direction

 

[greenthumb]

i overheard a bunch of guys talking about there bikes and a whole bunch of things. They were talking about
FORCE EQUALS MASS TIMES ACCELARTION.....(F= MxA)
What the hell does that mean?

think of it this way
bear with me - this is very rough

F - your bike has 100hp
M - it weighs 500lbs
A - it goes 0-60 in 3.5sec

so essentially it takes 100hp of force to make 500lbs go 0-60 in 3.5sec.
of course, you would never use any of these units of measure in this type of calculation, but it explains the concept.

this equation can be rearranged many ways too.
if you change any of the variables it, affects the outcome.
if you increase the force (hp), but keep the mass the same, it will accelerate quicker.
keep the force the same, lighten the weight, it will accelerate quicker.

read this for a more detailed explination http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion

 

[paul1149]

Look at it this way. Momentum is mass times velocity. Thus, the faster something goes the more momentum (energy) it has. But, absent friction and forces such as gravity and magnetism, that body would remain in motion without any more force acting on it. It's already had energy invested in it.

To change the velocity of that body, you need to apply force. And acceleration is defined as the change in velocity.

Thus force and acceleration are directly proportional to a given mass: the more force, the more acceleration. More acceleration means more force has been applied.

So if you take the equation, F=ma, and increase the Force while the Mass remains constant, the Acceleration has to increase.

 

[kvanderploeg]

A little explanation and demonstration from NASA:

NASA - Force Equals Mass Times Acceleration: Newton's Second Law

Kent

 

[wrightme43]

There you go!!!


Acceleration is change in direction of motion. It can be negitive or positive in any direction.

Mass is different than wieght.

A one kilogram mass will wiegh one kilogram on earth.
That same one kilogram mass on the moon with wiegh one sixth of a kilogram on the moon.

It will take the same force to accel or decel it and it will have the same potential energy.

Mainly most everything in life that is confusing boils down to people using the same definitions for words.

Communication is difficult when people dont use the same definitions.

 

[craig007]

force = a push or a pull on something
mass = the amount of "stuff" in something... on earth, weight is close enough
acceleration = the rate of change of velocity

the acceleration due to gravity is 32 feet per second per second (g). This is the same as about 22 miles per hour per second. So, this means that if you were riding your FZ at 22 mph and you executed an emergency stop...a 1 g stop, you would go from 22 mph to full stop in 1 second. Also, if you were stopped and executed a 1 g acceleration, you would go from 0 to 22 mph in 1 second.

F=ma tells us how force (push or pull) is related to mass and acceleration. Since m=F/a and a=F/m if you know two of them, you can calculate the third.

This is a really cool equation.

 

[Fred]

Force = the power of your engine.

Mass = the mass of you and the bike.

Acceleration = acceleration.

So, increase force, you increase acceleration by the same factor.

Decrease mass, you increase acceleration by the same factor.

More force good. Less mass good. Both equal more acceleration.

 

[AltitudeJunkie]

Sorry guys but I'm a Physics teacher with a masters degree in theoretical physics and this thread had made me cross.

Force is not the power of your bike at all, it's much more closely related to the torque, which is why (as we all know) bhp is useless if you don't have the torque to go with it.

Also, acceleration is not a change in direction, it's a change in velocity. Think about it, you can speed up (or accelerate) without changing direction (ie staying in a straight line).

F = M x A just says that if you have a heavy bike (lots of mass), you need a lot of torque to make it accelerate. On the other hand, if you have a lightweight bike, you can make it accelerate the same amount with less torque. This is probably why race bikes are so light, no?

Hope this helps. Sorry if it sound like a rant, nothing annoys me more than bad physics! :thumbup:

 

[GConn]

Sorry guys but I'm a Physics teacher with a masters degree in theoretical physics and this thread had made me cross.

Force is not the power of your bike at all, it's much more closely related to the torque, which is why (as we all know) bhp is useless if you don't have the torque to go with it.

Also, acceleration is not a change in direction, it's a change in velocity. Think about it, you can speed up (or accelerate) without changing direction (ie staying in a straight line).

F = M x A just says that if you have a heavy bike (lots of mass), you need a lot of torque to make it accelerate. On the other hand, if you have a lightweight bike, you can make it accelerate the same amount with less torque. This is probably why race bikes are so light, no?

Hope this helps. Sorry if it sound like a rant, nothing annoys me more than bad physics! :thumbup:

.....of course, you would never use any of these units of measure in this type of calculation, but it explains the concept...

Quoted text should be self explanatory, but simpler terms make it easier to explain things to people that don't have a master in physics...

 

[AltitudeJunkie]

Yeah, I understand and agree completely. The reason I posted is that the more we can drill home the idea that the amount of bhp your bike has is irrelevant, the more people may understand about their machines.

bhp doesn't get you from 0 to 60 in under 4 seconds, torque does, beacause torque is a measure of force, and F=MxA.

I realise that this might not help the OP a huge amount, but i thought it was worth saying anyway. If you don't agree, no problem.

 

[sweber_7]

i overheard a bunch of guys talking about there bikes and a whole bunch of things. They were talking about
FORCE EQUALS MASS TIMES ACCELARTION.....(F= MxA)
What the hell does that mean?

We just learned this in physics :spank:

 

[wrightme43]

Sorry guys but I'm a Physics teacher with a masters degree in theoretical physics and this thread had made me cross.

Force is not the power of your bike at all, it's much more closely related to the torque, which is why (as we all know) bhp is useless if you don't have the torque to go with it.

Also, acceleration is not a change in direction, it's a change in velocity. Think about it, you can speed up (or accelerate) without changing direction (ie staying in a straight line).

F = M x A just says that if you have a heavy bike (lots of mass), you need a lot of torque to make it accelerate. On the other hand, if you have a lightweight bike, you can make it accelerate the same amount with less torque. This is probably why race bikes are so light, no?

Hope this helps. Sorry if it sound like a rant, nothing annoys me more than bad physics! :thumbup:

I am all for you man. I am not a teacher and struggle very hard to explain things. My wording was wrong. Yours is much better.

 

[champion221elite]

F= M x A is basically a formula for quantifying kinetic energy, and it applies to all moving objects.

 

[Botch]

Force is not the power of your bike at all, it's much more closely related to the torque, which is why (as we all know) bhp is useless if you don't have the torque to go with it.

True, but the net result of this torque is actually a linear force, the force of the contact patch of the tire on the road. That linear force does act on the motorcycle's mass to accelerate it.
My BS and MS are in Engineering; you theoretical guys are always trying to confuse people! :justkidding: