PSYC 301 Lecture Notes - Lecture 7: Momentum, International System Of Units
Document Summary
Linear momentum: momentum is a vector, si units: kg /s. Impulse/momentum theorem: impulse of a force, j, impulse is a vector, si units: n s. The picture above represents a force applied by the bat on to the ball to change the velocity of the ball. Example 1: a baseball of mass = 0. 14 kg has initial velocity vi=-38m/s. After it is struck by the bat it has a velocity =+58m/s. Mass of rain per second hitting car roof, m = 0. 06 kg/s vi = 15 m/s (downwards) v f = 0 m/s: the hail rebounds (upwards) with final velocity. The change in velocity for hail: (v f vi) = (vf + vi). This is a larger number than for rain. Collision between two objects: internal forces: forces that the objects exert on each other, external forces: forces exerted on the objects by agents external to the system, internal forces cancel out by newton"s 3rd law.
