Answer:
The net force acting on the chair is 8 newtons, and the chair moves toward the left.
Explanation:
We can better understand this problem if we analyze it through a free body diagram. This free body diagram is attached as an image.
If we make a sum of forces acting over the chair we can find -20 + 12 = -8 [N]
The minus sign indicates that the chair is moving to the left.
Answer:
Figure A
Explanation:
At first, the inflated balloon is rubbed against the hair.
In this situation, the balloon is charged by friction: because of the friction between the surface of the balllon and the hair, electrons are transferred from the hair to the surface of the balloon.
As a result, when the balloon is detached from the hair, it will have an excess of negative charge (due to the acquired electrons).
Then, the balloon is placed in contact with the non-conducting wall.
The non-conducting wall is initially neutral (equal number of positive and negative charges).
Because the wall is made of a non-conducting material (=isolant), the charges cannot move easily through it. Therefore, even though the charges on the wall feel a force due to the presence of the electrons in the balloon, they will not redistribute along the wall.
Therefore, the charges on the wall will remain equally distributed, as shown in figure A.
Answer:
Explanation:
Given that,
A radio wave transmits 38.5 W/m² of power per unit area.
A flat surface of area A is perpendicular to the direction of propagation of the wave.
We need to find the radiation pressure on it. It is given by the formula as follows :
Where
c is speed of light
Putting all the values, we get :
So, the radiation pressure is 
.
Answer:
I'd say C is the answer they want, though my pedantic side wants to argue for B being true as well.
