Answer:
Change the wavelength to half while keeping velocity constant or change the wave velocity to 2 times while keeping wavelength constant.
Explanation:
The frequency of a wave can be defined as the rate of change of wave speed with respect to the wavelength of the wave.
Mathematically,

Here, v is the velocity, lambda is the wavelength, and f is the frequency of the wave.
If the observer want to double the frequency of the wave, then he should increase the wave velocity two times and take wavelength constant for this case or either he should half the wavelength of the wave to take the velocity of the wave constant.
67 is the answer . jen did
Answer:
Yes
Explanation:
The given parameters are;
The speed with which the fastball is hit, u = 49.1 m/s (109.9 mph)
The angle in which the fastball is hit, θ = 22°
The distance of the field = 96 m (315 ft)
The range of the projectile motion of the fastball is given by the following formula

Where;
g = The acceleration due to gravity = 9.81 m/s², we have;

Yes, given that the ball's range is larger than the extent of the field, the batter is able to safely reach home.
Answer:
B.convection currents in the mantle
Explanation:
Answer:
1.5F
Explanation:
Using
E= F/q
Where F= force
E= electric field
q=charge
F= Eq
So if qis tripled and E is halved we have
F= (E/2)3q
F= 1.5Eq=>> 1.5F