Uniform Circular Motion

🎯 Class Objective:

Relates Uniform Rectilinear Motion to motion with variable velocity, applies the equations of uniformly accelerated motion, and creates analogies between equations, graphs, and real-life situations to explain and predict motion behavior.

🎯 A) Quick Warm-Up (Concept Check)

1. Circle the correct option:
   
   

• In UCM, speed is constant / changing
  
  

• In UCM, velocity is constant / changing
  
  

• Centripetal acceleration points toward the center / away from the center
  
  

• If radius increases and speed stays constant, centripetal acceleration increases / decreases
  
  

⏱️ B) Period, Frequency, Angular Speed

1. A fan spins 3000 rpm. Find:
   
   

• frequency in Hz
  
  

• period T
  
  

• angular velocity ω

2. The Moon takes 27.3 days to orbit Earth. Find:
   
   

• frequency, period in seconds, and ω

🚗 C) Tangential Speed vs Angular Speed

1. A point on a rotating disk is at r=0.25 m and ω=12 rad/s.
   Find tangential speed v.
   
   

2. Two points A and B on the same disk:
   
   

• r_A = 0.10 m
  
  

• r_B​=0.30 m
  
  

• same ω
  Which point has greater v? Explain in one sentence.

🎢 D) Centripetal Acceleration + Force

1. A car takes a curve of radius r=50 m at v=14 m/s.
   Find a_c, the centripetal acceleration.
   
   

2. A 0.20 kg ball moves in a circle of radius 0.80 m at v=6 m/s.
   Find the centripetal force.

🧠 E) Real-Life / ICFES-Style Reasoning

1. A washing machine spins. Explain why clothes press against the drum wall (use inertia + centripetal force in your explanation).
   
   

2. A student says: “The centrifugal force is real and pushes outward.”
   Do you agree / disagree? Explain using reference frames.