A block of mass m = 10 kg is accelerated from rest along a horizontal surface by a spring with spring constant k = 4490 n/m. the surface is frictionless except for a rough patch for which the coefficient of kinetic friction is µk = 0.5. the block leaves the spring with speed vi = 2.8 m/s. use work and kinetic energy concepts to answer the following questions
(a)How much work is done by the spring as it accelerates the block?
(b)The block is measured to leave the rough spot with a final speed 1.3 v_f =1.3 m/s. How much work is done by the friction force as the block crosses the rough spot?
a)(a) 31.36 J, (b) -15.92 J
b)(a) 15.92 J, (b) -31.36 J
c)(a) 15.92 J, (b) 31.36 J
d)(a) -31.36 J, (b) 15.92 J