The best answer is C.
The stability of atoms depends on whether or not their outermost shell is filled with electrons. If the outer shell is filled with electrons, the atom is stable and therefore they do not need to react with other elements to become stable.
On the other hand, atoms with unfilled outer shells are unstable, and will usually form chemical bonds with other atoms to achieve stability. To achieve stability, atoms will form two types of chemical bonds called ionic bonds and covalent bonds.
Answer:
7.0s
Explanation:
Mass = 0.41kg
F= 81N
t = 0.22s
¤ = 29°
Lo = 86m
From impulse equation,
F*t = m* v
81 * 0.22 = 0.41 * v
Vo = 17.82 / 0.41
Vo = 43.46m/s
Vx= velocity across horizontal plane
Vy = velocity across vertical plane
Vx = Vo * cos ¤
Vy = Vo * sin ¤
Vx = 43.46 * cos 30° = 37.64 m/s
Vy = 43.46 sin 30° = 21.73 m/s
Distance travelled across the vertical plane,
L = Lo + Vy *t + ½gt²
0 = 86 + 21.73t - 4.9t²
4.9t² - 21.73t - 86 = 0
Solving for t in the quadratic equation,
t = 6.96 or -10.04
Using the positive root since time can't be negative, t = 6.96 approximately 7.0s
Answer:
gravity keeps the planets in orbit around the sun
