Laws Of Motion Question 362
Question: A 20 kg block is initially at rest on a rough horizontal surface.A horizontal force of 75 N is required to set the block in motion.After it is in motion, a horizontal force of 60 N is required to keep the block moving with constant speed.The coefficient of static friction is[AMU 1999]
Options:
A) 0.38
B) 0.44
C) 0.52
D) 0.60
Show Answer
Answer:
Correct Answer: A
Solution:
Coefficient of friction $ {{\mu } _{s}}=\frac{F _{l}}{R}=\frac{75}{mg}=\frac{75}{20\times 9.8} $
$ =0.38 $
