Internal vs. External forces

Question 1

External forces

Answer 1

Definition: Forces that originate outside the body or system being studied.

• Gravity: Pulls the body towards the ground, affecting activities like jumping or falling.
• Wind Resistance: Opposes forward motion during activities like running or cycling.
• Surface Friction: Provides traction, impacting movement (e.g., cleats for soccer or running shoes).

Question 2

Internal forces

Answer 2

Definition: Forces that originate inside the body.

• Muscle Contraction: Muscles create force to move bones (e.g., lifting weights or running).
• Ligament Tension: Ligaments stabilize joints and support actions (e.g., squats or throwing a ball).

Effect on Movement: Internal forces enable coordination and provide support during physical activities.