Answer:
Explanation:
The area of a circle is given b
A=πr²
Then,
dA/dr= 2πr
Also give that,
dr/dt=30m/hr, r=100m
We want to find dA/dt
dA/dt=dA/dr×dr/dt
dA/dt= 2πr × 30
dA/dt= 2 ×π ×100×30
dA/dt=18849.56m²/s.
The rate of the area is 18849.56m²/s
Answer:
E = 1.04*10⁻¹ N/C
Explanation:
Assuming no other forces acting on the proton than the electric field, as this is uniform, we can calculate the acceleration of the proton, with the following kinematic equation:

As the proton is coming at rest after travelling 0.200 m to the right, vf = 0, and x = 0.200 m.
Replacing this values in the equation above, we can solve for a, as follows:

According to Newton´s 2nd Law, and applying the definition of an electric field, we can say the following:
F = mp*a = q*E
For a proton, we have the following values:
mp = 1.67*10⁻²⁷ kg
q = e = 1.6*10⁻¹⁹ C
So, we can solve for E (in magnitude) , as follows:

⇒ E = 1.04*10⁻¹ N/C
1). Frequency = (1/period) = 1/(20sec) = (1/20) per sec .
2). Frequency= (3 waves) / (4 sec) = (3/4) (per sec)
Period = (1/freq) = 1/(3/4 per sec) = (4/3) sec
3). Speed= (freq) x (wavelength) (2 per sec) x (5 m) = (2 x 5) ( m per sec)
Speed doesn't depend on amplitude.
D I believe because it’s not a nor B and I don’t believe it’s C