Describe a situation. For each: a. Draw an interaction...

Name: Problem 1, Chapter 7: Physics for Scientist and Engineers: A Strategic Approach
Uploaded: 2021-05-15T16:16:45-08:00
Duration: 3 min 50 s
Channel: Suzanne W.
Description: Describe a situation. For each: a. Draw an interaction diagram, following the steps of Tactics Box 7.1 b. Identify the "system" on your interaction diagram. c. Draw a free-body diagram for each object in the system. Use dashed lines to connect the members of an action/reaction pair. A weightlifter stands up from a squatting position while holding a heavy barbell across his shoulders.

Describe a situation. For each: a. Draw an interaction diagram, following the steps of Tactics Box 7.1 b. Identify the "system" on your interaction diagram. c. Draw a free-body diagram for each object in the system. Use dashed lines to connect the members of an action/reaction pair. A weightlifter stands up from a squatting position while holding a heavy barbell across his shoulders.

Describe a situation. For each:
a. Draw an interaction diagram, following the steps of Tactics Box 7.1
b. Identify the "system" on your interaction diagram.
c. Draw a free-body diagram for each object in the system. Use dashed lines to connect the members of an action/reaction pair.
A weightlifter stands up from a squatting position while holding a heavy barbell across his shoulders.

Key Concepts

Action-Reaction Pairs

Action-reaction pairs are a concept from Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. In diagrammatic analysis, these pairs are visually connected, often using dashed lines, to indicate that forces occur in matched pairs and help ensure consistency when applying force balance to a system.

Free-Body Diagram

A free-body diagram is a simplified illustration used in physics and engineering to show all external forces acting on a single object or component. By isolating the object and representing forces such as gravity, normal force, and applied loads, this diagram aids in solving for net force and acceleration using Newton's laws.

Interaction Diagram

An interaction diagram is a visual representation that maps out all the forces or interactions among various objects or components in a scenario. It helps in understanding how objects influence each other by illustrating the path of forces and the exchange of actions, which is crucial for analyzing problems in mechanics or physics.

System Identification

System identification involves defining the boundaries of the system under analysis. This process helps to determine which objects or parts of the interaction are considered internal to the system and which are external. Clearly identifying the system is essential for simplifying and correctly applying physical laws to the problem at hand.

Transcript

00:01 So we need to draw an interaction diagram of a weightlifter that stands up from a squatting position while holding a heavy barbell across his shoulders.

00:11 Okay, so just to kind of give us a sketch first of what this looks like.

00:17 So sketch it first, then do the interaction diagram, then deal with the system, and then deal with the free body diagram.

00:27 So he is standing on the surface.

00:31 This is the earth.

00:34 Here is our very beautifully drawn guy.

00:41 And he's going to have ridiculously long arms for right now so that he can hold a barbell.

00:47 Okay.

00:48 So we know that he is in equilibrium because as he stands up, he's not moving after he stands up.

00:57 So the net force will be zero.

01:01 The barbell is having an upward contact force.

01:06 The gravitational force should be downwards.

01:08 So our interaction.