When you climb, earth exerts gravitational force on pack in downward direction(pointing towards the center of earth).
In order to climb, you need to work against work done by gravity on the pack.
Hence work done by you = work done by gravity on pack
= Force x displacement = 70 x 30 = 2100 J.
So you need to do 2100 joules of work to lift your pack.
Power is the rate of work done.
Therefore power = work done by you/time(in seconds)
= 2100/600 =3.5 watts
During a total lunar eclipse, the Moon located in the umbra.
The answer is letter A. For a total lunar eclipse to occur, the Sun, Earth and
Moon must be aligned in a straight line. The Earth’s umbra complete covers the
Moon. The earth’s umbra is about 870,000 miles wide.
Answer:
The statements A and D are true
The statements B and C are false
Explanation:
The force between charges can be explained by the Coulomb's Law.
According to Coulomb:
1 - Like charges always repel each other
2- Unlike or opposite charges always attrack each other
3- Force between 2 charges is given by:

where F is the force between 2 charges and r is the distance between 2 charges.
We can see that Force F is inversely proportional to the distance r
Which means that when F increase, r decreases and when F decreases, r increases
Answer:
Forces between molecules
Explanation:
The tensions between molecules are the characteristic that explains variances in the specific heat capacity of two substances.
This means that a substance's specific heat capacity will increase or be higher the closer its atoms are bound together. As a result, it differs for the different states of matter, such as solid, liquid, and gas.
The two competing forces that keeps earth orbiting the sun is gravity and inertia