Answer:
= 2.83
Explanation:
F number (N) is given by the formula;
F- number = f/D
where f = focal length of lens and D = diameter of the aperture
Therefore;
F number = 17 cm/6 cm
<u> = 2.83</u>
Answer:
t = 39.04 1010 year
Explanation:
This is a nuclear disintegration exercise that is governed by the equation.
N = N0 e (-lam t)
The average life time is related to nuclear activity
T ½ = ln 2 / lam
Let's use these two equations for exercise, let's start by finding nuclear activity
Lam = ln 2 / T ½
Lam = ln 2 / 4.9 10 10
Lam = 0.14146 10-10 y-1
They tell us that the relationship atoms
No / N = 0.0040
Let's look
No / N = 1/0040
N/No = 250
Let's calculate the time
(-lam t) = ln (N / No)
, t = - 1 / lam ln (n / No)
t = - 1 / 0.14146 10-10 ln (250)
t = 39.04 1010 year
A). balanced force
b). unbalanced force
There's no such thing as either of these. A group of two or more forces can be balanced or unbalanced. A single force can't be.
c). gravitational force ... doesn't cause an object to move in a circle;
Drop a stone from the roof of a tall building and watch it fall.
It goes straight down, not in a circle.
d). centripetal force ... force directed toward the center of a circle,
causes an object to move in a circle.
Answer:
The reason is because the pressure of the air inside the room drops with time which makes opening the door to require an increased amount of force to make up for the reduced pressure inside the room
Explanation:
From the kinetic theory of gases we have the following relation;
Where:
K = Boltzmann constant
T = Temperature
m = Mass
MW = Molecular weight
V = Volume
= Root mean square velocity
Whereby the room door is closed, the kinetic energy of the air particles will be used up such that the average velocity of the particles will decrease, given that the volume of the room is constant, the pressure inside the room will drop below the original pressure outside the room such that the force on the door due to the outside pressure is larger than the force on the door from inside the room requiring a larger amount of force to overcome the resistance of the now higher outside pressure force.
