An atom is defined as having the same number of electrons (negative charge), protons (positive charge) and neutrons (no charge). This means that it will have the same amount of negative and positive charge, giving it a net zero charge. On the other hand, an ion has different amount of electrons and protons.
D. lenses focus light , mirrors do not
Explanation:
In order to find out if the keys will reach John or not, we can use the formula of projectile motion to find the maximum height reached by the keys:
H = V²Sin²θ/2g
where,
V = Launch Speed = 18 m/s
θ = Launch Angle = 40°
g = 9.8 m/s²
Therefore,
H = (18 m/s)²[Sin 40°]²/(2)(9.8 m/s²)
H = 6.83 m
Hence, the maximum height that can be reached by the projectile or the keys is greater than the height of John's Balcony(5.33 m).
Therefore, the keys will make it back to John.
"The total distance traveled divided by the time it takes to travel the distance"
That's actually a pretty good definition of average speed. <em>(A)</em>
Net Force = (mass) x (acceleration) (Newton #2)
Net Force = (50 kg) x (6 m/s² down)
Net Force = (50 * 6) (kg-m/s² down)
<em>Net Force = 300 Newtons down</em>
