6. f = 128.62
, T= 0.0077775 s
7. f = 2.2 *
, T = 4.545 *
s
8. 32.64 
9. 3.29 *

Explanation:
Step 1:
6.
For light and sound v = fλ
where v represents the velocity
f represents the frequency
λ represents the wavelength
λ = 2.69 m
v = 346 m/s
f = v/λ = 346/2.69 = 128.62 
Time period is the reciprocal of frequency
T = 1/128.62 = 0.0077775 s
Step 2:
7.
λ = 110 cm = 1.1 m
v = 2.42*
m/s
f = 2.42*
/1.1 = 2.2 *

T = 1/(2.2*
) = 4.545 *
s
Step 3:
8.
λ = 10.6 m
v = 346 m/s
f = v/λ = 346/10.6 = 32.64 
Step 4:
9.
λ = 5.89 *
m
v = 1.94 *
m/s
f = v/λ = 3.29 *

Answer: The gravitational
Explanation: The student is pushing the box so u have to have gravitational force so it could move
Answer:
(C) HBr is an acid .......
Answer:

the mass of body B must be greater than the mass of body A
Explanation:
Newton's second law establishes a linear relationship between the force, the mass of the body and its acceleration
F = m a
a = F / m
Let's analyze this expression tells us that the force is of equal magnitude for the two bodies, but body A goes faster than body B, this implies that it has more relationships
a_A > a_B
Therefore, for this to happen, the mass of body B must be greater than the mass of body A