The weight I 151.9 N because the weight equals the mass times the gravitational force

**Answer:**

E. Coefficient of linear expansion

**Answer:**

73.5 m/s

**Explanation:**

The position of the first ball is:

y = y₀ + v₀ t + ½ at²

y = h + (0)(18) + ½ (-9.8)(18)²

y = h − 1587.6

The position of the second ball is:

y = y₀ + v₀ t + ½ at²

y = h + (-v) (18−6) + ½ (-9.8)(18−6)²

y = h − 12v − 705.6

Setting the positions equal:

h − 1587.6 = h − 12v − 705.6

-1587.6 = -12v − 705.6

1587.6 = 12v + 705.6

882 = 12v

v = 73.5

The second ball is thrown downwards with a speed of 73.5 m/s

The m value because it’s mass. This will not change throughout the problem because an object can not gain mass