# Mechanics: Momentum and Collisions

## Momentum and Collisions: Audio Guided Solution

#### Problem 1:

Determine the momentum of …

a. … an electron (m= 9.1 x10-31 kg) moving at 2.18 x 106 m/s (as if it were in a Bohr orbit in the H atom).
b. … a 0.45 Caliber bullet (m = 0.162 kg) leaving the muzzle of a gun at 860 m/s.
c. … a 110-kg professional fullback running across the line at 9.2 m/s.
d. … a 360,000-kg passenger plane taxiing down a runway at 1.5 m/s

## Audio Guided Solution

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## Habits of an Effective Problem Solver

• Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
• Identify the known and unknown quantities in an organized manner. Equate given values to the symbols used to represent the corresponding quantity - e.g., m = 1.50 kg, vi = 2.68 m/s,  F = 4.98 N, t = 0.133 s, vf = ???.
• Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
• Identify the appropriate formula(s) to use.
• Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.

Get more information on the topic of Momentum and Collisions at The Physics Classroom Tutorial.