Water as it's the highest specific heat capacity
Hope this helps x
Answer:
Let No be initial no of atoms
N = N0 / 2 after 1 half-life
N = N0 / 4 after 2 half-lives
So after 2 half-lives 20 of the 80 atoms remain
Answer:
1 second later the vehicle's velocity will be:

5 seconds later the vehicle's velocity will be:

Explanation:
Recall the formula for the velocity of an object under constant accelerated motion (with acceleration "
"):

Therefore, in this case
and 
so we can estimate the velocity of the vehicle at different times just by replacing the requested "t" in the expression:

The free-body diagram of the forces acting on the flag is in the picture in attachment.
We have: the weight, downward, with magnitude

the force of the wind F, acting horizontally, with intensity

and the tension T of the rope. To write the conditions of equilibrium, we must decompose T on both x- and y-axis (x-axis is taken horizontally whil y-axis is taken vertically):


By dividing the second equation by the first one, we get

From which we find

which is the angle of the rope with respect to the horizontal.
By replacing this value into the first equation, we can also find the tension of the rope:
force times gravity (FG) =mass times gravity (mg)