Torque and Rotational Kinetic Energy Relationship

  • #1
alichoudhry57
1
0
I am wondering if it is possible to calculate either the Kinetic Energy or Rotational Kinetic Energy of an object if we have the Power (kW), Torque (Nm), and Speed (RPM) of the object.
 

Answers and Replies

  • #2
russ_watters
Mentor
22,060
9,163
I am wondering if it is possible to calculate either the Kinetic Energy or Rotational Kinetic Energy of an object if we have the Power (kW), Torque (Nm), and Speed (RPM) of the object.
Depends, but probably not. Do we have a continuous function for those? Is there any more info you can provide on your scenario?
 
  • #3
Lnewqban
Homework Helper
Gold Member
2,644
1,434
I am wondering if it is possible to calculate either the Kinetic Energy or Rotational Kinetic Energy of an object if we have the Power (kW), Torque (Nm), and Speed (RPM) of the object.
Welcome @alichoudhry57 !
Objects can’t have those by themselves, as power refers to a transfer of energy, you need at least another object or substance receiving that energy.
Therefore, could you please clarify your reference to that object?
 
  • Like
Likes russ_watters and topsquark
  • #5
jbriggs444
Science Advisor
Homework Helper
11,583
6,240
I am wondering if it is possible to calculate either the Kinetic Energy or Rotational Kinetic Energy of an object if we have the Power (kW), Torque (Nm), and Speed (RPM) of the object.
Power tells you the rate at which energy is flowing through the object. It will not tell you how much energy or angular momentum the object contains. A drive shaft with an attached flywheel and a second drive shaft without can have the same power and torque passing through and can be rotating at the same rate. But the amount of kinetic energy and angular momentum that the two contain can be dramatically different.

If you have torque in Nm and rotation rate in RPM then you can get power in kilowatts. Indeed, given any two of the three, you can calculate the one you do not know.

For power, first convert RPM to radians per second (multiply by 0.104719755). Multiply torque in Nm by rotation rate in rad/s to get power in watts. Then divide by 1000 to get power in kilowatts.

Edit: scooped by @Baluncore on the power from torque and speed calculation.
 

Suggested for: Torque and Rotational Kinetic Energy Relationship

Replies
3
Views
488
Replies
16
Views
481
  • Last Post
Replies
3
Views
436
Replies
1
Views
236
  • Last Post
Replies
11
Views
500
  • Last Post
Replies
1
Views
331
Replies
4
Views
8K
Replies
5
Views
228
Replies
15
Views
582
Top