Power Smithen
Work Energy-
A pulley system conisisting of three pulleys is used to lift a pallet
of
bricks Weighing 600N
through a height of 40m. The
force required to lift the pallet
at a
steady speed is 210N and the rope is pulled through a distance of 120m

(a) Neglecting
the mass
of the pulleys and rope, calculate the useful work
done in lifting the pallet. ​

Identify and describe the three ways that mutations affect organisms.

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

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.)