In the first case:
when we heat any gas, the Kinetic Energy of the molecules increases, making it collide more frequently with the surface, increasing the pressure
more collisions with the surface means more force applied on it, which would push the piston harder than before, moving it outwards.
In the second case:
since the molecules inside the beaker have no way to escape, they would keep compressing the more you push the beaker downwards.
since there is the same number of molecules and lesser volume to cover, the molecules will start colliding with the surfaces more frequently, which would resist the downward force.
<em>another way to think about it is to imagine yourself where the trapped air is. you would be happy when the room is spacious but if the wall starts moving towards you, you would resist the change by your body because you need space to exist. making it harder for the wall to move.</em>
<em>pushing the beaker downwards will keep getting harder and harder the more you push until you reach a point where the molecules will be completely compact. applying even more force forces the molecules to enter water, removing the air that was resisting it all and making you able to get the beaker in water.</em>
Third case:
just like in the first case, the heated air will apply force on the surface, including the cork. which would pop off when enough force is applied.
A) heterogeneous mixture & I believe B?
I know A is correct though
An image that can be projected on a screen is a real image. A real image can be larger than the original object.
good luck
Answer:
The net force acting on the person is 5.34 N acting upwards
Explanation:
The information given are;
Mass of the person = 55.0 kg
Density of the person = 1010 kg/m³
Body volume of the person = Mass/Density = 55/1010 = 0.0545 m³
Weight of the person = Mass × Gravity = 55 × 9.81 = 539.55 N↓
Where the density of water = 1000 kg/m³, we have;
Upthrust = weight of the water displaced = Mass of the water displaced × Gravity
Mass of the water displaced = Density of water × Volume of the water
Mass of the water displaced = Density of water × Body volume of the person
= 1000 × 0.0545 = 54.5 kg
The Upthrust = 54.5 × 9.81 = 534.21 N↑
Given that the net force, 
acting is the sum of the mass of forces acting on the person which are the weight acting downward and the upthrust acting upwards
We have;
F(Net) = 534.21↑ - 539.55↓ = 5.34 N↑
The net force acting on the person = 5.34 N upwards.
