The mechanical advantage of an inclined plane is the ratio of the inclined surface to the vertical height. simple machines with greater mechanical advantage reduce the force required to lift a load. in which case is the effort required the least?
a) raising a 100 kg box to a height of 1 m using an inclined plane of length 5 m
b) raising a 100 kg box to a height of 2 m using an inclined plane of length 6 m
c) raising a 200 kg box to a height of 1 m using an inclined plane of length 4 m
d) raising a 200 kg box to a height of 2 m using an inclined plane of length 8 m

Lower the mass lesser the force or effort required

so lesser effort will be required for 100 Kg box as compared to 200 kg box

now less effort will be required for raising an object to lesser height

hence less effort will be required for 1 m than 2m

Hence the correct answer is

raising a 100 kg box to a height of 1 m using an inclined plane of length 5 m

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.