How fast does a rocket ship have to go for its length to be contracted to 99% of its rest length?

Will you chech and finish these for me, because i am stumped with them.

The text compares alternating current with direct current. how are they different? a alternating current reverses direction in the electrical wiring. direct current flows in one direction only. b direct current reverses direction in the electrical wiring. alternating current flows in one direction only. c direct current is powered by solar energy. alternating current is powered by electrical energy. d alternating current does not move in the electrical wiring. direct current does move in the electrical wiring.

The standard cell potential (e°cell) for the reaction below is +0.63 v. the cell potential for this reaction is when the concentration of zn2+ = 1.0 m and the concentration of pb2+ = 2.0 x 10-4 m. pb2+(aq) + zn(s) > zn2+(aq) + pb(s)