BITSAT 2019 Paper

(a) The two springs are in parallel.
∴ Effective spring constant,
k = k1+k2
Now, frequency of oscillation is given by
f =

1

2p

√

k

m

or, f =

1

2p

√

k1+k2

m

........(i)
When both k1 and k2 are made four timestheir original values, the new frequency is given by
f′ =

1

2p

√

4k1+4k2

m

f′ =

1

2π

√

4(k1+k2)

m

= 2(

1

2π

√

(k1+k2)

m

) = 2f