I think it would be because solid wood is a lot heavier than plastic
Answer by YourHope:
Hi! ^-^
At what age is a child likely to learn to sit up without support?
I would say Five months if you position the child but Nine months for the baby to sit up by themselves! So the answer is Nine months!
Have a BEAUTIFUL day~
Answer:
![M = \left[\begin{array}{ccc}cos \ 60&0\\0&-sin \ 60\end{array}\right]](https://tex.z-dn.net/?f=M%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dcos%20%5C%2060%260%5C%5C0%26-sin%20%5C%2060%5Cend%7Barray%7D%5Cright%5D)
Explanation:
To find the matrix, let's decompose the vectors, the rotated angle is (-60C) for the prime system
x ’= x cos (-60)
y ’= y sin (-60)
we use
cos 60 = cos (-60)
sin 60 = - sin (-60)
we substitute
x ’= x cos 60
y ’= - y sin 60
the transformation system is
![\left[\begin{array}{ccc}x'\\y'\end{array}\right] = \left[\begin{array}{ccc}cos 60&0\\0&-sin60\end{array}\right] \ \left[\begin{array}{ccc}x\\y\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%27%5C%5Cy%27%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dcos%2060%260%5C%5C0%26-sin60%5Cend%7Barray%7D%5Cright%5D%20%5C%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%5C%5Cy%5Cend%7Barray%7D%5Cright%5D)
x '
the transformation matrix is
Answer:
A. Provides H in water - Arrhenius acid
B. Provides OH - in water - Arrhenius base
C. Proton donor - Bronsted-Lowry acid
D. Proton acceptor - Bronsted-Lowry base
E. Electron pair donor - Lewis base
F. Electron pair acceptor - Lewis acid.
Explanation:
Definition:
A Lewis base is any substance, such as the OH- ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an electron-pair donor.
A Bronsted-Lowry acid is a chemical species that donates one or more hydrogen ions in a reaction. Also, a Bronsted-Lowry base accepts hydrogen ions.
An Arrhenius acid is a substance that dissociates in water to form hydrogen ions or protons. In other words, it increases the number of H+ ions in the water. Also, an Arrhenius base dissociates in water to form hydroxide ions, OH-.
I’m pretty sure the answer is A
