Q. A horizontal platform vibrates with simple harmonic motion in the horizontal direction with a period 2 s. A body of mass 0.5 kg is placed on the platform. The coefficient of static friction between the body and platform is 0.3. What is the maximum frictional force on the body when the platform is oscillating with amplitude 0.2 m? Assume $\pi^{2} = 10 = g.$
A) 0.5 N
B) 1 N
C) 1.5 N
D) 2 N
Explanation
(b) Maximum force on body while in SMH
$= m\omega^{2}a = 0.5 \times \left( \frac{2\pi}{2} \right)^{2} \times 0.2 = 1\ N$
Maximum force of friction$= \mu mg = 0.3 \times 0.5 \times 10 = 1.5$ N
Since the maximum force on the body due to SHM of the platform is less than the maximum possible frictional force, so the maximum force of friction will be equal to the maximum force acting on body due to SHM of platform $ie$, 1 N
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.