Answer:
A) and B) are correct.
Explanation:
If the object is at rest, it means that no net force is exerted on it.
As the object experiences a downward gravitational force from Earth, in order to be at rest, it must experience an upward force with the same magnitude as the gravitational force on the object.
This force is supplied by the normal force, which can adopt any value in order to meet the condition imposed by Newton´s 2nd Law, and is always perpendicular to the surface on which the object is placed (in this case, the ground).
At a molecular level, this normal force is supplied by the bonded molecules of the ground that behave like small springs being compressed by the molecules of the object, exerting an upward restoring force upward on them.
So, the statements A) and B) are true.
Answer:
sound waves and water waves are completely different. water waves shakes energy over the surface of sea, while sound waves thump energy through the body of the air.
To calculate the mass of the fuel, we use the formula
Here, m is the mass of fuel, V is the volume of the fuel and its value is and is the density and its value of 0.821 g/mL.
Substituting these values in above relation, we get
Thus, the mass of the fuel 247 .94 kg.
Answer:
The weight of the air above is smaller
Explanation:
As altitude increases, the amount of gas molecules in the air decreases. The air becomes less dense than air nearer to sea level. This is what people mean by “thin air”. Thin air exerts less pressure than air at a lower altitude.