Help with physics impulse problem

In summary, impulse is a measure of the change in momentum of an object and can be calculated by multiplying the force applied to an object by the time over which the force is applied. It is related to, but distinct from, momentum, and can cause a change in an object's motion. Impulse is also directly related to the conservation of momentum, as when the total external force on a system is zero, the total momentum remains constant. This means that the impulse on one object is equal and opposite to the impulse on another object, resulting in no overall change in momentum for the system.
  • #1
Arden
5
0
I just need a little help getting past the first step. I have already converted rpm to rad/sec.

120 J are done on a fly wheel to raise its speed from 60rpm to 160 rpm. Find its moment of inertia.


How do I convert 120J to power

and how do I set up the inertia half
 
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  • #2
Think in terms of angular kinetic energy.
 
  • #3


To convert 120J to power, you need to divide the energy (Joules) by the time it takes to do the work. In this case, the time is not given, so we cannot calculate the power. However, we can solve for the moment of inertia using the given information.

To set up the inertia half, you need to use the formula for impulse: impulse = change in momentum. In this case, the impulse is equal to the work done on the flywheel, which is 120J. The change in momentum can be calculated using the formula: change in momentum = mass x change in velocity. Since the mass of the flywheel is not given, we can use the formula for rotational inertia, which is equal to mass x radius^2. So, the formula becomes: impulse = mass x radius^2 x change in angular velocity.

Now, we can substitute the given values: 120J = mass x radius^2 x (160rpm - 60rpm) converted to rad/s. Since you have already converted the rpm to rad/s, you can simply plug in the values and solve for the moment of inertia.

I = (120J) / (radius^2 x change in angular velocity)

I hope this helps you move past the first step and solve the problem. Remember to always double check your units and make sure they are consistent throughout the calculation. Good luck!
 

1. What is impulse in physics?

Impulse is a measure of the change in momentum of an object. It is equal to the force applied to an object multiplied by the time over which the force is applied.

2. How do you calculate impulse?

Impulse can be calculated by multiplying the force applied to an object by the time over which the force is applied. The formula for impulse is J = F * Δt, where J is impulse, F is force, and Δt is the change in time.

3. What is the difference between impulse and momentum?

Impulse and momentum are related concepts, but they represent different quantities. Momentum is a measure of an object's motion, while impulse is a measure of the change in an object's momentum.

4. How does impulse affect an object's motion?

Impulse causes a change in an object's momentum, which in turn affects its motion. If an object experiences a large impulse, its momentum will change significantly, resulting in a change in its velocity or direction of motion.

5. How is impulse related to the conservation of momentum?

Impulse is directly related to the conservation of momentum. When the total external force acting on a system is zero, the total momentum of the system remains constant. This means that the impulse on one object is equal and opposite to the impulse on another object, resulting in no overall change in momentum for the system.

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