on touching electroscope gets positively charged, so answer is B. conduction
<span>We know that pressure is the force applied into a surface, in our case the wall of the room, so then first we will calculate the surface of this wall:
S = 2.2 * 3.2 = 7.04 m2
Then we also know the atmospheric pressure in normal conditions is 1 atm. That is the same 1 atm = 101325 Pascals or 101325 N/m2
Now we need to use the formula : P = F/S where P is pressure, F is force and S is surface to calculate the force:
F = P * S = 101325 * 7.04 = 713,328 Newtons
Conclusion: the force acts on the wall due the air inside the room is 713,328 N</span>
Answer:
a)
a = 2 [m/s^2]
b)
a = 1.6 [m/s^2]
c)
xt = 2100 [m]
Explanation:
In order to solve this problem we must use kinematics equations. But first we must identify what kind of movement is being studied.
a)
When the car moves from rest to 40 [m/s] by 20 [s], it has a uniformly accelerated movement, in this way we can calculate the acceleration by means of the following equation:

where:
Vf = final velocity = 40 [m/s]
Vi = initial velocity = 0 (starting from rest)
a = acceleration [m/s^2]
t = time = 20 [s]
40 = 0 + (a*20)
a = 2 [m/s^2]
The distance can be calculates as follows:

where:
x1 = distance [m]
40^2 = 0 + (2*2*x1)
x1 = 400 [m]
Now the car maintains its speed of 40 [m/s] for 30 seconds, we must calculate the distance x2 by means of the following equation, it is important to emphasize that this movement is at a constant speed.
v = x2/t2
where:
x2 = distance [m]
t2 = 30 [s]
x2 = 40*30
x2 = 1200 [m]
b)
Immediately after a change of speed occurs, such that the previous final speed becomes the initial speed, the new Final speed corresponds to zero, since the car stops completely.

Note: the negative sign of the equation means that the car is stopping, i.e. slowing down.
0 = 40 - (a *25)
a = 40/25
a = 1.6 [m/s^2]
The distance can be calculates as follows:

0 = (40^2) - (2*1.6*x3)
x3 = 500 [m]
c)
Now we sum all the distances calculated:
xt = x1 + x2 + x3
xt = 400 + 1200 + 500
xt = 2100 [m]
To make a educational guess based on the your observations
Answer:
A motivational speech for a to be scientist. Crazy experiments and more you have the right to be whatever you adore. Your young yet strong everything will come along. I believe in you and so should you since your becoming a scientist you’ll acquire it soon. You’ll discover new things and sight to see when you become a scientist make sure to call me. :)
Explanation:
Hope it’s good I made up a couple words that rhyme good luck!