Mechanics - elestic string

One end of a light elastic string, of natural length 1.25m and modulus of elasticity 24N, is attached to a fixed point O on a horizontal table. The other end of the string is fixed to a particle of mass 1.6 kg on the table. The particle is pulled along the table until the length of the string is 1.5m.

a) calculate the tension in the string

b) the particle is now released.

i) Given that the table is smooth, calculate the initial acceleration of the particle.

ii) Given that the table is rough and that the particle is on the point of slipping, calculate the coefficient of friction.

OK i think i have only ever answered questions that have inelastic string which is why im struggling.

with an inelastic string the tension would be (1.6) - T = (1.6)(9.8) right?

part bi i think maybe i use the same equation but instead of (9.8) i put 'a' then solve for a?

part bii i think that the point of slipping f = mew*r ??