Jenna asked in Science & MathematicsPhysics · 9 years ago

# Physics- Velocity and Kinetic Energy?

Two particles of mass m1 = 1.7 kg and m2 = 3.5 kg undergo a one-dimensional head-on collision as shown in the figure below. Their initial velocities along x are v1i = 15 m/s and v2i = - 7.5 m/s. The two particles stick together after the collision (a completely inelastic collision). (Assume to the right as the positive direction.)

a) Find the velocity after the collision. (m/s)

b) How much kinetic energy is lost in the collision? (J)

Relevance
• Anonymous
9 years ago

CONSERVATION of LINEAR MOMENTUM

(m1v1i)i+(m2v2i)=(m1vif)+(m2v2f)

since they the collision is inelastic

v1f=v2f=vf

making the equation

(m1v1i)+(m2v2i)=(m1+m2)vf

(1.7kg)(1.5m/s)+(3.5kg)(-7.5m/s)=(1.7kg + 3.5kg)vf

-23.7kgm/s=5.2kg(vf)

vf=(-23.7kgm/s)/(5.2kg)

***vf=-4.56 m/s***

For the kinetic energy

is the KE (lost) for each particle?

if I got that right,

use the formula:

Just substitute values and use

KE=(1/2)m1v1f-m1v1i----->for KE lost in particle 1

and

KE=(1/2)m2v2f-m2v2i----->for KE lost in particle 2

Hope this helps you!

^^