Kinetic energy and momentum of two objects

[wilmerena]

do 2 objects that have the same kinetic energy necessarily have the same momentum? I can't think of a simple example

 

[AKG]

do 2 objects that have the same kinetic energy necessarily have the same momentum? I can't think of a simple example

Consider a 5 kg mass going at 50 m/s, thus having 6.25 kJ of kinetic energy. Now, a mass of 125 kg going 10 m/s also has 6.25 kJ of kinetic energy. However, the first object has a momentum of 250 kg*m/s, and the second has 1250 kg*m/s of momentum.

 

[wilmerena]

thanks so much =o) !

 

[wilmerena]

what if they both have 0 momentum, so does it follow that the kinetic energy of the system doesn't have to be zero as well? or does it?

 

[Doc Al]

what if they both have 0 momentum, so does it follow that the kinetic energy of the system doesn't have to be zero as well? or does it?

Think about it. For a simple object:
$$KE = 1/2 mv^2$$
$$momentum = mv$$
The only way an object can have zero momentum is if its speed (v) is what? Then what is its KE?

 

[wilmerena]

thanks again, i think i just spaced out on that one ;oP