The lowest note on a piano is 27.5 Hz. To fit inside the piano,
the string for the low note can't be
longer than 1.20 m. If it takes the
full length, what is the speed of
the wave in the string?
(Unit = m/s)

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.