Explanation:
Given that,
Mass of the cart, 
Mass of the cart 2,
Final speed of cart 2, 
Final speed of cart 1 is 0 as it comes to rest.
Let us assume that the initial velocity of the cart 2 is 0. So using the conservation of linear momentum as :

So, the initial velocity of the 1.0-kg cart is 0.9 m/s.
The volume increases, but the surface area remains the same
Axial Tilt and Sun Energy
This axial tilt means that during the Earth's journey around the sun the poles receive varying amounts of sunlight. The equator, however, receives relatively consistent sunlight all year. The consistency of energy means the equator's temperature stays relatively constant all year.
Answer:
= 2
Explanation:
During nuclear fusion, two lighter nuclei of elements combine to form heavy nucleus and also energy is released;
During the process of hydrogen fusion a nucleus of deuterium is formed from two protons with emission of a neutrino.
In this case deuterium fuses with hydrogen nuclei to form helium-3 and also release energy.
That is;
2/1 H + 1/1 H = 3/1 He + energy