Answer:
A
Explanation:
I only think its A because of the gravity part...sorry im not good at explaining
Answer:
Speed of lighter ball is 4 m/s.
Explanation:
Applying the principle of conservation of linear momentum,
momentum before collision = momentum after collision.

+
= 
- 

= 3 kg,
= 8 m/s,
= 2 kg,
= 0 m/s ( since it is at rest),
= 2 m/s,
= ?
(3 x 8) + (2 x 0) = (8 x 2) - (2 x
)
24 + 0 = 16 - 2
2
= 16 - 24
2
= -8
= 
= -4 m/s
This implies that the light ball moves at the speed of 4 m/s in the opposite direction of the heavier ball after collision.
Work = (force) x (distance)
To lift each baby, force = 90N,
distance = 1.0 something, let's say 1.0 meter .
Work to lift each baby = (90N) x (1.0 meter) = 90 joules.
Work to lift both of them = 2 x 90 joules = 180 joules.
The building is in solid phase. Its molecules are arranged in a ver compact manner that is why it takes a definite shape and volume. When it is heated, the kinetic energy of the molecules increases. This is characterized by more frequent collisions. The rise in temperature causes the molecules to move rapidly by vibrating. When it reaches an amount of energy that causes the solid to change phase, this is called the latent energy. The molecules break their form and move farther away from each other until it resembles that of a liquid melting. This phase change is known as melting. The energy that must be reached to achieve melting is the latent heat of fusion.