Nuetrons+protons. and number 7 is electrons and protons
Answer:
19.3 g/mL
Explanation:
The following data were obtained from the question:
Mass (m) = 12.4 kg
Volume (V) = 642 mL.
Density (D) =.?
Next, we shall convert 12.4 kg to grams. This can be obtained as follow:
1 kg = 1000 g
Therefore,
12.4 kg = 12.4 × 1000
12.4 kg = 12400 g
Therefore, 12.4 kg is equivalent to 12400 g.
Finally, we shall determine the density of the gold as follow:
Density is simply defined as the mass of the substance per unit volume of the substance. It can be represented mathematically as:
Density (D) = mass (m) / volume (V)
D = m/V
With the above formula, the density of gold can easily be obtained as follow:
Mass (m) = 12400 g
Volume (V) = 642 mL.
Density (D) =.?
D = m/V
D = 12400/642
D = 19.3 g/mL
Therefore, the density of hold is 19.3 g/mL
The volume of the balloon is 77.0 L<span>.</span><span />
Answer: The correct answer is C.
Explanation: Frictional force is the contact force which resists the motion of one surface on another.
Mathematically,

where,
f = frictional force
= Coefficient of friction
N = normal force acting on a body
We need to find the ratio of force of sliding friction ( which is a type of frictional force) and the normal force acting on an object. This will be equal to coefficient of friction.
