Answer:
About 5 % of the universe is visible.
Estimates are that 68 % of the universe consists of "dark energy" and 27% of the universe consists of "dark matter". Currently 95 % of the universe is not currently visible to the scientists involved (cannot be explained by means that we know).
Answer:
1020g
Explanation:
Volume of can=

Mass of can=80g=
1Kg=1000g
Density of lead=
By using 
We have to find the mass of lead which shot can it carry without sinking in water.
Before sinking the can and lead inside it they are floating in the water.
Buoyancy force =

Where
Density of water
Mass of can
Mass of lead
Volume of can
Substitute the values then we get




Hence, 1020 grams of lead shot can it carry without sinking water.
Answer:
9155 years old
Explanation:
We use the following expression for the decay of a substance:

So we first estimate the value of k knowing that the half-life of the C14 is 5730 years:

so, now we can estimate the age of the artifact by solving for"t" in the equation:

which we can round to 9155 years old.
The 78g box, since it has less weight, would accelerate faster. If you had a frictionless surface, and you conducted this experiment, both boxes, without any outside forces, would accelerate at the same rate forever. However, in this problem we must assume the surface is not frictionless. Friction is determined by weight; the more weight, the more friction. Since the 78g box has less weight, it has less friction, making it easier to push with less force.