Quick question for the lorry drivers

therealnerd2 said:
I understand what you're trying to say. Do you mind if i try and explain?

A ball is rolling down a hill at an angle T. The ball has mass M. The gravitational force on the ball down the slope is therefore F = MA = M*G*Sin(T). So that's the force, which includes mass. However, as i've used before, F=M*A, so A = G * Sin(t). So mass is not a factor in the acceleration equation.
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Acceleration due to mavity is a constant but a lighter truck will have a slower terminal velocity as the resisting aerodynamic forces acting on it which are identical to the heavier truck will equal the force F derived from gravitational pull.
The heavier truck has a greater force acting upon it due to mavity and therefore can counter greater aerodynamic resistance giving it a higher terminal velocity.

It's basic physics - primary school stuff.
 
Scuzi said:
Acceleration due to mavity is a constant but a lighter truck will have a slower terminal velocity as the resisting aerodynamic forces acting on it which are identical to the heavier truck will equal the force F derived from gravitational pull.
The heavier truck has a greater force acting upon it due to mavity and therefore can counter greater aerodynamic resistance giving it a higher terminal velocity.

It's basic physics - primary school stuff.
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Absolutely. As i've said MANY MANY TIMES, air resistance IS affected by mass!

Lol!
 
therealnerd2 said:
Absolutely. As i've said MANY MANY TIMES, air resistance IS affected by mass!

Lol!
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NO its not.

The weight overcomes the rolling resistance and air resistance by a larger amount that an empty truck, therefore the residual force accelerates the heavier truck more that the lighter one.

Also a truck of higher mass has higher potential energy at the top of the hill.
 
therealnerd2 said:
I understand what you're trying to say. Do you mind if i try and explain?

A ball is rolling down a hill at an angle T. The ball has mass M. The gravitational force on the ball down the slope is therefore F = MA = M*G*Sin(T). So that's the force, which includes mass. However, as i've used before, F=M*A, so A = G * Sin(t). So mass is not a factor in the acceleration equation.
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edit: too slow i see there has been about 5 posts now and its been cleared up :p
 
Jez said:
Its way too late and ive been out of college for way too long to sit down and crunch through all that jazz;

Basically speaking the component force acting down the slope will be greater given the greater mass of the truck combined with mavity, this goes into one of the S=UT+0.5AT^2 or one of those equations and it will equate to a bigger value for A (so long since ive done any of this and im in bed knackered and cant get my head around it right now).

Without understanding any of this it translates to real world (obvious) findings anyway, so i know given the right equations and real figures it would be correct :p
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You also are completely correct. Lets all now go to sleep (together)

AHHHHH gotcha before the ninja :D
 
Wang said:
I know what you are saying, but assuming neglible wind resistance and friction, they would accelerate at the same rate, to the same speed. I just wanted to clarify my meaning, as this:
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You can assume that for air as they are the same form, friction on the heavier truck will be greater anyway, full deployment of trailor wheels and more tyre deflection yet in practice its obvious the heavier truck accelerate faster.


Terminal velocity only applies to falling objects, stop using it in trucks :P
 
therealnerd2 said:
Ok. Yes. You are correct.
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To be honest dude im actually slightly worried that someone of 21 doesnt understand this stuff, its taught at the lower end of secondary school, and even without education is it really that hard to see that a 44 tonne object is going to exert a greater force then a 1 tonne object down a slope? :p

Least i can rest in peace now, i thought i was going mad :D
 
Jez said:
It not even physics though, its just obvious. 44 tonnes at the top of a hill on wheels, compared with 1 tonne. Which is going to be harder for a man to stop using his foot? The component of force is so obviously going to be more that i actually feel slightly worried for the people posting to the contrary above.:(
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It will be harder for the truck to stop as it has more momentum. the equation P=mv where P is momentum, m mass and v velocity shows it would take a larger force to change this,the force is the push or pull that is applied to an object to CHANGE its momentum. It doesn't mean the lorry is travelling faster, it's just that if it weighs twice as much as the empty one, it will have twice as much momentum, but the same velocity.
 
Jez said:
To be honest dude im actually slightly worried that someone of 21 doesnt understand this stuff, its taught at the lower end of secondary school, and even without education is it really that hard to see that a 44 tonne object is going to exert a greater force then a 1 tonne object down a slope? :D
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Yeah I guess you should be even more worried that i'm in the third year of an Applied Mathematics degree at Cambridge.

I promised myself i'd leave this thread, but i can't resist this:
http://www.teachertube.com/view_video.php?viewkey=9f27a4b9e4abd169d6e4
Sorry Scuzi :(
 
You Spoilt my fun.
I need to walk into a door now to restore the balance :D
 
norm said:
Who decided on 56mph being the speed limit for HGVs? Seems somewhat arbitrary.
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56 MPH is used as it allows for the vehicle to overspeed on hills etc on motorways.

The limit for LGV's being 60MPH.

Something about speed & hills, I don't know what there on about. ;)


Trucks are obviously heavier than feathers. :p;):D:D
 
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