Lecture 23-24: Elastic Collisions and Momentum

Types of Collisions

Elastic Collisions and Inelastic Collisions

Elastic Collision

No kinetic energy is lost for this type of collision.

Inelastic Collision

Some kinetic energy is lost for this type of collision.

Perfectly Inelastic Collision

Objects stick together and Final velocity is common for this type of Collision.

Conservation of Kinetic Energy (State 1 and State 2) & Conservation of Momentum.

Important concepts for solving collisions: _________

Formula for ________ when body B is initially at rest.

Final Velocity of V_B2X or the Final Velocity of Body B along the horizontal axis.

Elastic Collision: Formula for ________ when body B is initially at rest.

Reflected, Boosted, Transferred Kinetic Energies.

Elastic Collision: 3 Cases affected by mass of bodies.

• M_a<M_b

• M_a>M_b

• M_a=M_b

V_a2x = -V_a1x Where body A is reflected back, velocity remains almost the same, and V_B2x = 0 as Body B is almost stationary.

Elastic Collision: 3 Cases affected by mass of bodies.

• M_a<M_b

V_a2x = V_a1x Where body A is almost unchanged in the same direction, velocity remains almost the same, and V_B2x = 2V_a1x as Body B moves faster.

Elastic Collision: 3 Cases affected by mass of bodies.

• M_a>M_b

V_a2x = 0 Where body A stops after collision, and V_B2x = V_a1x as Body B moves same as A before collision.

Elastic Collision: 3 Cases affected by mass of bodies.

• M_a=M_b

same magnitude but opposite sign

In 1D elastic collision between two bodies, the relative velocities before and after the collision have the ____________.

Relative velocity has the same magnitude before and after the collision.

Whenever this condition is satisfied, kinetic energy is conserved.

Product of (Mass x Position or Velocity) / Total Mass

Center of Mass Calculations for Position and Velocity is ________.

Conservation of Momentum

If the vector sum of the external forces on a system is zero, the total momentum of the system is constant.