<span>3.2 grams
The first thing to do is calculate how many half lives have expired. So take the time of 72 seconds and divide by the length of a half life which is 38 seconds. So
72 / 38 = 1.894736842
So we're over 1 half life, but not quite 2 half lives. So you'll have something less than 12/2 = 6 grams, but more than 12/4 = 3 grams.
The exact answer is done by dividing 12 by 2 raised to the power of 1.8947. So let's calculate 2^1.8947 power
= 12 g / (e ^ ln(2)*1.8947)
= 12 g / (e ^ 0.693147181 * 1.8947)
= 12 g / (e ^ 1.313305964)
= 12 g / 3.718446464
= 3.227154167 g
So rounded to 2 significant figures gives 3.2 grams.</span>
Explanation:
Water evaporates from the surface of the earth and through the leaves of the plants and trees by absorbing the heat energy from the surrounding.
This water then converts into vapour and goes up into the atmosphere where the temperature is low in the troposphere and condenses to form the clouds. During the cloud formation the heat form the vapour is absorbed in the troposphere.
These clouds when get saturated then fall in the form of precipitation of water, snow etc. Replenishing back the water of the earth.
The car traverses a distance 
after time 
according to
where 
is its acceleration, 10 m/s^2. The time it takes for the car to travel 25 m is
5 is pretty close to 4, so we can approximate the square root of 5 by 2. Then the car's velocity 
after 2 s of travel is given by
which makes C the most likely answer.
Answer:
p = FΔt = 8.0 N(60 s) = 480 N•s
Explanation:
not asked for, but in that time a frictionless 18 kg mass on a horizontal surface will have change velocity by 480/18 = 26.7 m/s.
An impulse results in a change of momentum.
Answer:
lambda = 343 m/s divided by 340 Hz = 1.009 seconds
Hope it helps and have a wonderful day!
