Astuffed toy with a mass of 0.900 kilograms sits on the edge of a bed at a height of 0.830 meters. if the toy falls off the bed, what will its kinetic energy be at a height of 0.500 meters?

Kinetic energy at 0.500 m is 2.9106 Joules.

Explanation:

Mass of the stuffed toy = 0.900 kg

Height at which toy is sitting = 0.830 m

Potential energy at this point will be maximum and kinetic energy will be minimum.

P.E=

But the mechanical energy will remain conserve throughout the system.At 0.830 m the mechanical energy will be

M.E= P.E+K.E = 7.3206 J + 0 J=7.3206 J

Potential energy at 0.500 m

Mechanical energy at this point will remain the same as that of the 0.830 m.

M.E= P.E'+K.E'=7.3206 J=4.41 J+ K.E'

K.E'=2.9106 J

Kinetic energy at 0.500 m is 2.9106 Joules.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation:

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).