👋 Hello! I'm Alphonsio the robot. Ask me a question, I'll try to answer.

# Helicopters rotor blades could spin at high speed of 400 rpm. Find the angular displacement in radians for 7 hours operation.

The rotor blades spin at 400 revolutions per minute. So, in seven hours, the blades perform revolutions.

Since one revolution is radians, we can deduce the angular displacement of the blades : radians.