For every O ion, two Na ions are needed to balance charges. Which ratio represents the relationship between Na and O?
2 Na:1 O
Answer:
1.) Covering the ceiling and walls with soft perforated boards
2.) Hanging curtains round the hall
3.) Having more opening in the wall.
Explanation:
This is due to what we called Reverberation due to poor acoustic properties.
Reverberation can be reduced by;
1.) Covering the ceiling and walls with soft perforated boards
2.) Hanging curtains round the hall
3.) Having more opening in the wall.
Answer:
28.2 m/s
Explanation:
The range of a projectile launched from the ground is given by:
where
v is the initial speed
g = 9.8 m/s^2 is the acceleration of gravity
is the angle at which the projectile is thrown
In this problem we have
d = 81.1 m is the range
is the angle
Solving for v, we find the speed of the projectile:
By Newton's second law, the net force on the object acting parallel to the surface is
∑ F = F[applied] - F[friction] = (8k g) (3 m/s²)
If F[applied] = 30 N, then
30 N - F[friction] = 24 N ⇒ F[friction] = 6 N
so the answer is B.
