Answer:
Force, F = 77 N
Explanation:
A child in a wagon seem to fall backward when you give the wagon a sharp pull forward. It is due to Newton's third law of motion. The forward pull on wagon is called action force and the backward force is called reaction force. These two forces are equal in magnitude but they acts in opposite direction.
We need to calculate the force is needed to accelerate a sled. It can be calculated using the formula as :
F = m × a
Where
m = mass = 55 kg
a = acceleration = 1.4 m/s²

F = 77 N
So, the force needed to accelerate a sled is 77 N. Hence, this is the required solution.
Answer:
2 in front of water and 1 in front of oxygen
Explanation:
This question is describing balancing a chemical reaction. A balanced chemical reaction has the same number of atoms of each elements on both the reactant and product side. According to the question, the reactants contains 4 atoms of oxygen. The reactants give rise to water (H20) and O2 in the products side.
This reaction is most likely the decomposition of hydrogen peroxide (H2O2) as follows:
H2O2 (l) ----> H2O (l) + O2(g)
Based on the description, H2O2 will be 2H2O2 as it is said to contain four atoms of oxygen. This means that, in order to have a balanced equation, we must place coefficient 2 in front of water and coefficient 1 in front of oxygen. That is;
2H2O2 (l) ----> 2H2O (l) + O2(g)
It does not violate the law of conservation of energy. The oscillation stops when the energy is lost and the energy is lost because it becomes heat that is created by the air resistance and many other forces found in the surrounding of the oscillating spring.
Which source of information is generally considered credible?