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Overcast
2008-11-17, 00:23
I have a physics question on a review for an exam that I don't understand. The question reads:

"Two people of equal mass, 6 meters apart, attempt a tug of war on frictionless ice. If they pull on opposite ends of the rope with equal forces, each slides 3 meters to a point midway between them. Suppose instead that only one person pulls and the other fastens the rope around their waist. How far does each person slide? (Neglect any effects of the rope's mass).

Thanks.

xXPhoenixFireXx
2008-11-17, 00:48
Same thing happens. Conservation of momentum.

Forces and equal and opposite reactions type deal. While the person not "pulling" Isn't doing work, his body still exerts force on the rope cause he has mass.

twotimintim
2008-11-17, 00:50
Same thing happens. Conservation of momentum.

Forces and equal and opposite reactions type deal. While the person not "pulling" Isn't doing work, his body still exerts force on the rope cause he has mass.

seconded

bobfish
2008-11-17, 14:04
thirded.

Warsie
2008-11-20, 06:59
Same thing happens. Conservation of momentum.

Forces and equal and opposite reactions type deal. While the person not "pulling" Isn't doing work, his body still exerts force on the rope cause he has mass.

thanks dude. I was going to say 4.5 m and 1.5 haha.

im new to this..

Child_molester
2008-11-22, 15:25
I have a physics question on a review for an exam that I don't understand. The question reads:

"Two people of equal mass, 6 meters apart, attempt a tug of war on frictionless ice. If they pull on opposite ends of the rope with equal forces, each slides 3 meters to a point midway between them. Suppose instead that only one person pulls and the other fastens the rope around their waist. How far does each person slide? (Neglect any effects of the rope's mass).

Thanks.

MORE IMPORTANTLY:
How the fuck are they standing still on frictionless ice?

courtesy_flusher
2008-11-23, 13:56
I thought since only one is pulling you'd have half the force so they'd each only slide 1.5 m

xarf
2008-11-23, 18:16
I thought since only one is pulling you'd have half the force so they'd each only slide 1.5 m

True, but they pull until they smash into each other presumably.

The Chip Shop Guy
2008-11-25, 23:23
I thought since only one is pulling you'd have half the force so they'd each only slide 1.5 m

True, but they pull until they smash into each other presumably.

Nope. They are still both pulling with equal force.

When you extert a force onto someones face, their face exerts the exact same force, in the opposite direction, onto your hand.

Likewise when your car tires exert a force onto the road, the road (due to friction) causes the exact same force back onto your car. Because your car is lighter than the plannet, your car moves faster.

So when the boy A pulls on boy B; boy B pulls with the same force back onto boy A no matter what.

They end up in the middle again. Newton's Third Law.

P.S. It's not "Every reaction has an equal and opposite reaction" bullshit. That's the worst explanation ever.

xarf
2008-11-26, 02:37
Nope. They are still both pulling with equal force.

When you extert a force onto someones face, their face exerts the exact same force, in the opposite direction, onto your hand.

Likewise when your car tires exert a force onto the road, the road (due to friction) causes the exact same force back onto your car. Because your car is lighter than the plannet, your car moves faster.

So when the boy A pulls on boy B; boy B pulls with the same force back onto boy A no matter what.

They end up in the middle again. Newton's Third Law.

P.S. It's not "Every reaction has an equal and opposite reaction" bullshit. That's the worst explanation ever.

The forces on each of them are equal, however I would argue that the force on each is less than if they were both pulling. This is because the force on each is equal to the tension in the rope, and if they're both pulling the tension will clearly be higher.

But yeah, they'll obviously end up in the middle no matter what (provided they're the same mass,etc).

blackfox26
2008-12-05, 02:02
They will slide along the ice forever. Once they slide and collide with each other, each one of them will slide off into opposite directions. Since there is no friction on the ice, they won't stop.

Mantikore
2008-12-05, 03:40
They will slide along the ice forever. Once they slide and collide with each other, each one of them will slide off into opposite directions. Since there is no friction on the ice, they won't stop.

air resistance :):):)

xarf
2008-12-05, 05:14
They will slide along the ice forever. Once they slide and collide with each other, each one of them will slide off into opposite directions. Since there is no friction on the ice, they won't stop.

Not if they hold onto the rope they won't.

SLice_760
2008-12-14, 04:46
I wish I had totse to explain physics to me last year instead of my shitty physics teacher. :(

I barely failed... his tests were hard and harshly graded, and he didn't really teach us anything, however when someone explained the shit to me I understood just fine.

Oh well.