Collisions & Motion (Momentum & Energy) Video Lessons

Concept

# Problem: If two particles have equal momenta, are their kinetic energies equal?a. Yes, always.b. No, never.c. No, except when their speeds are the same.d. Yes, as long as they move along parallel lines.

###### FREE Expert Solution

Momentum:

$\overline{){\mathbf{p}}{\mathbf{=}}{\mathbf{m}}{\mathbf{v}}}$

Kinetic energy:

$\overline{){\mathbf{K}}{\mathbf{E}}{\mathbf{=}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{m}}{{\mathbf{v}}}^{{\mathbf{2}}}}$

Momentum is directly proportional to mass and velocity. If we half mass and double velocity, momentum will not change.

Kinetic energy is directly proportional to mass and square of velocity. If we half mass and double velocity, the kinetic energy will double.

96% (146 ratings)
###### Problem Details

If two particles have equal momenta, are their kinetic energies equal?

a. Yes, always.

b. No, never.

c. No, except when their speeds are the same.

d. Yes, as long as they move along parallel lines.