<span>This statement simply implies that the 50 million tons of coal will produce the same energy output in one year as the 0.6 million barrels per day of oil. Assuming coal is more plentiful than oil, this is significant as 50 million tons is much smaller than 219 million barrels of oil.</span>
Answer:
Scientists have identified about a dozen major and several minor tectonic plates
Answer:
The density of salt water is more than that of density of fresh water, so so salt and fresh water makes a difference in floating of ships.
If,

then, with 3x time t, (suppose, new distance is h)




Therefore, new distance h will be 9 times bigger than distance d.
answer: c
The period of a simple pendulum is given by:

where L is the pendulum length, and g is the gravitational acceleration of the planet. Re-arranging the formula, we get:

(1)
We already know the length of the pendulum, L=1.38 m, however we need to find its period of oscillation.
We know it makes N=441 oscillations in t=1090 s, therefore its frequency is

And its period is the reciprocal of its frequency:

So now we can use eq.(1) to find the gravitational acceleration of the planet: