Multiple choice

The force required to drag a circular flat plate of radius $5\mathrm { cm }$ on the surface of water is $( \mathrm { ST }$ of water is $75 dyne/cm).$

  1. $30 dyne$
  2. $60 dyne$
  3. $750 dyne$
  4. $750 \pi dyne$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The force required to lift a circular plate from a liquid surface is F = Surface Tension * Perimeter. The perimeter of the plate is 2 * pi * r. Given r = 5 cm and ST = 75 dyne/cm, F = 75 * 2 * pi * 5 = 750 * pi dyne.

AI explanation

To drag the circular plate on the surface of water, the required force must overcome the surface tension acting along the entire circumference of the plate. The formula for this force is F = T * L, where T is the surface tension and L is the circumference 2 * pi * r. Using the given radius of 5 cm and surface tension of 75 dyne/cm, the calculation is F = (75 dyne/cm) * (2 * pi * 5 cm) = 750 * pi dyne.

Keep practicing — related questions