Question

Please somebody help me

Answer 1

x=Asinwt. v=Awcoswt

KE=1/2 mv^2=1/2 m(A^2)(w^2)cos^2wt

PE=1/2 kx^2

k=mw^2

PE=1/2 m(w^2)(A^2)sin^2wt

According to the question,

KE=PE

cos^2wt=sin^2wt

coswt=sinwt

wt=45°

x=Asinwt=Asin45=A/√2

so, answer is option (b)

Answer 2

Answer:

P. E = K. E

1/2 kx^2 = 1/2 k(A^2 - x^2)

1/2 kx^2 = 1/2kA^2 - 1/2kx^2

2(1/2kx^2) = 1/2kA^2

2x^2 = A^2

x = A/√2.