Calculate the translational speed of a cylinder

In summary, the cylinder reached the top of the incline and had potential energy. It then became kinetic energy and had the equation m*g*h = Σ KE. At the bottom, ω was found to be v/r which solved the equation.
  • #1
Bones
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Homework Statement


Calculate the translational speed of a cylinder when it reaches the foot of an incline 11 m high. Assume it starts from rest and rolls without slipping.


Homework Equations





The Attempt at a Solution


How do you find the speed when you only have the height of the incline?
 
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  • #2
Bones said:

Homework Statement


Calculate the translational speed of a cylinder when it reaches the foot of an incline 11 m high. Assume it starts from rest and rolls without slipping.

How do you find the speed when you only have the height of the incline?

The height gives you potential energy.

You get KE at the bottom, but be careful you also have rotational KE in the cylinder since it rolled without slipping.
 
  • #3
I am not sure what the equation is. The only one I found was v=sqrt 10/7gH which was not right.
 
  • #4
Bones said:
I am not sure what the equation is. The only one I found was v=sqrt 10/7gH which was not right.

Show your equations and perhaps we can see where you are going wrong.
 
  • #5
There's this one: 1/2Mv^2+1/2Icm(omega)^2+Mgy
But I am not sure where to get all this information from just having the height of the incline.
 
  • #6
Bones said:
There's this one: 1/2Mv^2+1/2Icm(omega)^2+Mgy
But I am not sure where to get all this information from just having the height of the incline.

Ok. You have your potential energy. And at the bottom what's happened to that PE? It's become KE for this problem. So whjat you have then is

m*g*h = Σ KE = 1/2 m*v2 + 1/2*I*ω2

But what is ω ? Happily ω = v/r

Why happily? Because the moment of inertia also will have a term that relates to r.

Why don't you look up the moment of a cylinder and solve the rest of the problem?
 
  • #7
The moment of inertial for a cylinder is 2/5Mr^2, but I am still not sure how to solve this. I keep getting 12.4m/s which is not correct.
 

FAQ: Calculate the translational speed of a cylinder

What is the formula for calculating the translational speed of a cylinder?

The formula for calculating the translational speed of a cylinder is v = rω, where v is the translational speed, r is the radius of the cylinder, and ω is the angular velocity.

What is the difference between translational speed and rotational speed?

Translational speed refers to the linear motion of an object, while rotational speed refers to the circular motion of an object. Translational speed is measured in meters per second, while rotational speed is measured in radians per second.

How does the mass of the cylinder affect its translational speed?

The mass of the cylinder does not directly affect its translational speed. However, a heavier cylinder may require more force to move at a certain speed, as described by Newton's second law, F = ma.

Can the translational speed of a cylinder change?

Yes, the translational speed of a cylinder can change if there is a change in its angular velocity or if an external force is applied to the cylinder. Otherwise, it will remain constant due to the principle of inertia.

What are some real-life applications of calculating the translational speed of a cylinder?

Knowing the translational speed of a cylinder can be useful in various fields such as engineering, physics, and sports. For example, engineers may need to calculate the speed of a rotating cylinder to ensure the safe operation of machinery. In sports, the translational speed of a cylinder can be used to analyze the performance of athletes, such as the speed of a spinning discus or a rotating ice skater.

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