Question
Question: Two blocks of mass 10 kg and 2 kg are connected by an ideal spring of spring constant 1000 N/m and t...
Two blocks of mass 10 kg and 2 kg are connected by an ideal spring of spring constant 1000 N/m and the system is placed on a horizontal surface as shown.
The coefficient of friction between 10 kg block and surface is 0.5 but friction is assumed to be absent between 2 kg and surface. Initially blocks are at rest and spring is unstretched then 2 kg block is displaced by 1 cm to elongate the spring then released. Then the graph representing magnitude of frictional force on 10 kg block and time t is : (Time t is measured from that instant when 2 kg block is released to move)
A
B
C
D
None of these
Answer
Explanation
Solution
fs = kx
(where fs is frictional force on 20 kg block and xis instantaneous elongation or compression in spring)
fs = k (A cos wt)
\ | fs | = kA |cos wt|