Physics Help please!

[Lizabath]

Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

 

[Lizabath]

plenty of engineering majors here I am sure, give me some help please.

I will post some new pics for the correct answers

 

[Darien]

Originally posted by: Lizabath
I will post some new pics for the correct answers

LOL! That's one way to do it.

<--- Majoring in physics.

You should try to work these problems out, because they're pretty basic.

At least show us what you're thinking.

 

[element]

Originally posted by: Lizabath
plenty of engineering majors here I am sure, give me some help please.

I will strip on cam for the correct answers

teh w00tness!


Torque=newton meters, so your job should you choose to accept it, is to figure out how to find the force in newtons and multiply it by 0.92.

then strip away..... j/k

 

[fawhfe]

Originally posted by: element

Originally posted by: Lizabath
plenty of engineering majors here I am sure, give me some help please.

I will strip on cam for the correct answers

teh w00tness!


Torque=newton meters, so your job should you choose to accept it, is to figure out how to find the force in newtons and multiply it by 0.92.

then strip away..... j/k

lol thats not even how you do the problem. The length is only useful for finding the moment.

 

[element]

its only part of it, the rest is even easier #1.

and #2, I don't see you coming up with any better.

besides what I wrote is right.

 

[George P Burdell]

Originally posted by: element

Originally posted by: Lizabath
plenty of engineering majors here I am sure, give me some help please.

I will strip on cam for the correct answers

teh w00tness!


Torque=newton meters, so your job should you choose to accept it, is to figure out how to find the force in newtons and multiply it by 0.92.

then strip away..... j/k

:beer:

 

[sciencewhiz]

Originally posted by: Darien
At least show us what you're thinking.

 

[Forsythe]

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Explain to me the highlighted. My english is pretty badass normally, but here i hit the end. Though i am studying physics.

 

[Goosemaster]

Originally posted by: Forsythe

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Explain to me the highlighted. My english is pretty badass normally, but here i hit the end. Though i am studying physics.

Think of a mirror.

 

[TuxDave]

Do you know how to calculate the moment of inertia for various things like circular discs or rods or point masses etc...? Because if you can do that, then you can basically do both these problems.

 

[fawhfe]

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Just write down the eqations. For 1: T=I*a (torque=moment*angular accel if you use diff variables) and for 2: I=sum over all masses of (m*r^2).

 

[element]

Originally posted by: fawhfe

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Just write down the eqations. For 1: T=I*a (torque=moment*angular accel if you use diff variables) and for 2: I=sum over all masses of (m*r^2).

lol that's not even how you do the problem, you're not given the moment.

 

[element]

Originally posted by: Goosemaster

Originally posted by: Forsythe

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Explain to me the highlighted. My english is pretty badass normally, but here i hit the end. Though i am studying physics.

Think of a mirror.

You're going to scare the crap outta him.

 

[sciencewhiz]

Originally posted by: element

Originally posted by: fawhfe
Just write down the eqations. For 1: T=I*a (torque=moment*angular accel if you use diff variables) and for 2: I=sum over all masses of (m*r^2).

lol that's not even how you do the problem, you're not given the moment.

It's easier to solve the first one another way, but it's quite easy to calculate the moment of a rod pivoting on one side.

 

[Yossarian]

I am holding a 1 kg uniform rod of 20cm length, compute the torque I'm applying to the end of it :evil:

 

[fawhfe]

Originally posted by: element

Originally posted by: fawhfe

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Just write down the eqations. For 1: T=I*a (torque=moment*angular accel if you use diff variables) and for 2: I=sum over all masses of (m*r^2).

lol that's not even how you do the problem, you're not given the moment.

Christ, I thought the point was that she'd do SOME work in manipulating the problem to fit the eq's she has to work with. The moment of a rod on its end can be found in any physics book, or even calculated if you're bored enough.

 

[element]

Originally posted by: sciencewhiz

Originally posted by: element

Originally posted by: fawhfe
Just write down the eqations. For 1: T=I*a (torque=moment*angular accel if you use diff variables) and for 2: I=sum over all masses of (m*r^2).

lol that's not even how you do the problem, you're not given the moment.

It's easier to solve the first one another way, but it's quite easy to calculate the moment of a rod pivoting on one side.

Yeah ok kinda reminds me of another part of this thread. Did you read the whole thread?

 

[Goosemaster]

Originally posted by: element

Originally posted by: Goosemaster

Originally posted by: Forsythe

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

Explain to me the highlighted. My english is pretty badass normally, but here i hit the end. Though i am studying physics.

Think of a mirror.

You're going to scare the crap outta him.

 

[element]

Originally posted by: Yossarian
I am holding a 1 kg uniform rod of 20cm length, compute the torque I'm applying to the end of it :evil:

take better measurements first.

 

[ActuaryTm]

Will solve above problems for photograph of a naked singularity.

 

[sciencewhiz]

Originally posted by: element
Torque=newton meters, so your job should you choose to accept it, is to figure out how to find the force in newtons and multiply it by 0.92.

Nope. You multiply it by something other then .92. think uniform rod.

 

[element]

Originally posted by: sciencewhiz

Originally posted by: element
Torque=newton meters, so your job should you choose to accept it, is to figure out how to find the force in newtons and multiply it by 0.92.

Nope. You multiply it by something other then .92. think uniform rod.

the length of the bat is 0.92, which is the same as the radius by which it rotates.

 

[Legendary]

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

For question #1, technically wouldn't you have to know the length of his arms, where the force is coming from, etc.?

 

[element]

Originally posted by: Legendary

Originally posted by: Lizabath
Here is the question:
A softball player swings a bat, accelerating it from rest to 3.0 rev/s in a time of 0.19 s. Approximate the bat as a 2.5-kg uniform rod of length 0.92 m, and compute the torque the player applies to one end of it.

and

A hypothetical molecule consists of two identical atoms whose total mass is 6.3E-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.3E-46 kg·m2. Estimate, from the given data, the effective distance between the atoms.

For question #1, technically wouldn't you have to know the length of his arms, where the force is coming from, etc.?

it's all in the wrist. but yeah some of it is in the hips too. since the arm length isn't given , it must not be taken into account for this problem. technically it really is a little of both, hip motion and wrist motion. you'd have to take a ratio of which affects it more and then avg the 2 weighted to that ratio.