To lift a load of 100 n a distance of 1 m an effort of 25 n must be applied over an inclined plane of length 4 m. what must be done to lift the load 2 m, using the same effort? a. use an inclined plane of length 8 m. b. use an inclined plane of length 2 m. c. use an inclined plane of length 10 m d. use an inclined plane of length 16 m.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)