Answer:
Cohesive forces are greater than adhesive forces
Step-by-step explanation:
The attractive forces between water molecules and the wax on a freshly-waxed car (adhesive forces) are quite weak.
However, there are strong attractive forces (cohesive forces) between water molecules.
The water molecules are only weakly attracted to the wax, so the cohesive forces pull the water molecules together to form beads
.
Hot-air balloons float because the air caught inside the balloon is heated up by a burner, making it less dense than the air outside. As the burner heats the air, it expands and some of the air escapes; that's what makes it less dense
Answer:
1. 505g is the mass of the aluminium.
2. The answer is in the explanation
Explanation:
1. To solve this question we need to find the volume of the rectangle. With the volume and density we can find the mass of the solid:
Volume = 7.45cm*4.78cm*5.25cm
Volume = 187cm³
Mass:
187cm³ * (2.702g/cm³) = 505g is the mass of the aluminium
2. When the temperature of a liquid increases, the volume increases doing the density decreases because density is inversely proportional to volume. And works in the same way for gases because the temperature produce more collisions and the increasing in volume.
Answer:
V ∝ abc
Explanation:
This task is a joint variation task involving only direct proportionality:
Direct variation is one in which two variables are in direct proportionality to each other. This means that as one increases, the other variable also increases and vice - versa.
Joint variation is one in which one variable is dependent on two or more variables and varies directly as each of them.
In this exercise:
If a ∝ b and a ∝ c, then a ∝ bc
Taking the above three proportionalities,
V ∝ a ∝ b ∝ c
V ∝ a ∝ bc
V ∝ abc
