Answer:
Iris
Explanation:
The pupil is where the light enters the eye, however, the iris is pupil tissue and is the one who regulates the amount of light that it lets through.
The iris opens or closes to allow a greater or lesser flow of light through the pupil.
In summary, the iris is responsible for regulating the amount of light that enters the eye.
Your position in meters will, measured relative to the starting point of the car behind you, be
x1(t) = 10 + 23.61 t - 1/2 4.2 t^2
his position will be
x2(t) = 16.67 t
Hence at any time the separation s(t) will be
s(t) = x1(t) - x2(t) = 10 + 6.94 t -2.1 t^2
Now I assume you mean that you will decelerate UNTIl you are driving at the legal speed limit (60 km/h). That will take you:
16.67 m/s = 23.61m/s - 4.2 m/s^2 * t
t = 1.65 seconds
What is the separation at that time? If it is still greater than zero, there will be no collision:
s(1.65) = 10 + 6.94 *1.65 -2.1 (1.65)^2 = 15.73 meters.
Hence you will NOT collide. The 1.65 s you calculated was the time needed to brake to the speed of 60 km/h.
Answer:
Weight=686.7N, 
, S.G.=0.933, F=17.5N
Explanation:
So, the first value the problem is asking us for is the weight of methanol. (This is supposing there is a mass of methanol of 70kg inside the tank). We can find this by using the formula:
W=mg
so we can substitute the data the problem provided us with to get:
which yields:
W=686.7N
Next, we need to find the density of methanol, which can be found by using the following formula:
we know the volume of methanol is 75L, so we can convert that to 
like this:
so we can now use the density formula to find our the methanol's density, so we get:
Next, we can us these values to find the specific gravity of methanol by using the formula:
when substituting the known values we get:
so:
S.G.=0.933
We can now find the force it takes to accelerate this tank linearly at 
F=ma
F=17.5N
