Question 18: a
question 19: b
question 20: c
A chemical compound consists of 2 or more chemical elements. They can be separated into simpler substances. Atoms of elements can be combined to form compounds. Molecules are groups of 2 or more atoms held together by chemical bonds. Minerals are chemical compound that can be found in nature. Valence is a measure of the combining power of an element.Answer: A. Atoms of elements.
Comes in pairs
Just like in Newton’s 3rd law, there is always an equal and opposite force
3.25 x 10^2 (ten to the second power)
Power P is the amount of energy E transferred or converted per unit time t, and is expression is:
P = E/t
The necessary energy to lift the box its the work of against the Gravity Force, and is given by:
E = mgh
Then the power is:
P = E/t
P = mgh/t
P = (45 kg)(9.8 m/s²)(1.7 m )/ 30
P = 24.99 W
<h2>P ≈ 25 W</h2>
