Answers:
a) 222.22 m/s
b) 800.00 km/h
Explanation:
The speed of a wave is given by the following equation:
Where:
is the speed
is the frequency, which has an inverse relation with the period 
is the wavelength
Solving with the given units:
This is the speed of the wave in km/h
Transforming this speed to m/s:

This is the speed of the wave in m/s
Answer:
hello your question is incomplete attached below is the complete question
answer :
20.16 v
Explanation:
The reading of the voltmeter at the instant the switch returns to position a
L = 5H
i ( current through inductor ) = 1/L ∫ V(t) d(t) + Vo
= 1/5 ∫ 3*10^-3 d(t) + 0 = 0.6 * 10^-3 t
iL ( 1.6 s ) = 0.6 * 10^-3 * 1.6 = 0.96 mA
Rm ( resistance ) = 21 * 1000 = 21 kΩ
The reading of the voltmeter ( V )
V = IR
= 0.96 mA * 21 k Ω = 20.16 v
The formula we will be using is;F = G m1 m2 / r^2
F earth = 308N
F moon = G me m2 / (81.3 * 0.27^2 RE^2) = 1/5.927 G me m2 / RE^2 = F earth / 5.927 = 52 N is the force of the earth
So the answer in this question is 52 N.
We know, F = m * a
Here, m = 140 g = 0.140 Kg
a = 25 m/s2
It would be: F = 0.140 * 25 = 3.5 N
So your answer would be 3.5N