Kinetic energy of N solid bodies

In summary, the book discusses N solid bodies with initial speed vi and final speed vi' after a shock to the system, and the difference in kinetic energy is given as the sum of the product of mass and the difference in squared speeds. However, the (1/2) factor is missing and it is not clear why. The author may have made a typo or left it out for convenience, but this should be noted for clarity in the calculations.
  • #1
Oddbio
Gold Member
46
0
This is a fairly simple question so I wasn't sure if it belongs here, but it is not a homework question. Just a question on something I'm reading.

The book says there are N solid bodies with initial speed vi (i=1, 2, 3, ..., N)
and final speed vi' after some shock to the system.

The book then says that the difference in kinetic energy is:
[tex]\sum_{i=1}^{N}m_{i}(v_{i}'^{2}-v_{i}^{2})[/tex]

But my question is, where did the (1/2) factor go from the kinetic energy?

I was even wondering if this has something to do with combining the sum for initial and final kinetic energies into a single script, but if I write the sum out using "j" for initial and "i" for final in the sums it comes out to be what they have but with a (1/2)... like I think it should.
Am I supposed to assume that this is just a typo? Even though several calculations are performed from that equation following its appearance.
I can't see any reason why it would be missing.
 
Physics news on Phys.org
  • #2
Hi Oddbio! :smile:
Oddbio said:
But my question is, where did the (1/2) factor go from the kinetic energy?

Am I supposed to assume that this is just a typo? Even though several calculations are performed from that equation following its appearance.
I can't see any reason why it would be missing.

Typo (or laziness of the author)! :rolleyes:

I assume that it makes no difference to the calculations because it's missing from both sides of every equation.

But the author still shouldn't leave it out without warning. :frown:
 

What is kinetic energy?

Kinetic energy is the energy an object possesses due to its motion.

How is kinetic energy calculated?

Kinetic energy is calculated using the formula KE = 1/2 * mass * velocity^2.

What is the relationship between kinetic energy and mass?

The kinetic energy of an object is directly proportional to its mass, meaning that as mass increases, kinetic energy also increases.

How is kinetic energy affected by velocity?

Kinetic energy is directly proportional to the square of an object's velocity, meaning that as velocity increases, kinetic energy increases at a faster rate.

Can kinetic energy be converted into other forms of energy?

Yes, kinetic energy can be converted into other forms of energy such as potential energy, thermal energy, or sound energy.

Similar threads

Replies
30
Views
2K
Replies
16
Views
1K
  • Mechanics
Replies
11
Views
956
Replies
7
Views
842
Replies
13
Views
1K
Replies
3
Views
878
Replies
6
Views
2K
Replies
15
Views
2K
Replies
3
Views
850
Back
Top