(a) 10cm/s,10cm/s2.It is given that the turntable is rotating with uniform angular velocity. Let the velocity be  ω .We have:v=rω⇒v∝r(P for constant ω)v′v​=r′r​⇒v′=2v​=10 cm/sSimilarly, we have: a′=2a​=10 cm/s2