# Mechanics: Vectors and Forces in Two-Dimensions

## Vectors and Forces in 2-D: Audio Guided Solution

#### Problem 4:

At one moment during a walk around the block, there are four forces exerted upon Fido - a 10.0 kg dog. The forces are:

Fapp = 67.0 N at 30.0° above the horizontal (rightward and upward)
Fnorm = 64.5 N, up
Ffrict = 27.6 N, left
Fgrav = 98 N, down

Resolve the applied force (Fapp) into horizontal and vertical components, then add the forces up as vectors to determine the net force.

## 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 = 1.25 kg, µ = 0.459, vo = 0.0 m/s,  Ø = 41.6º, 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.