Speed of wave is 8000 m/s.
Answer:
Explanation:
Speed is the measure of ratio of distance to time taken to cover that distance. In other words, speed is the measure of how fast the object can be move in a given time interval. So in this case, the wave is considered as object . And wave consists of wavelength in place of distance and frequency as reciprocal of time interval.
So speed of wave is calculated as the product of wavelength and frequency.
As the wavelength is given as 20 m and the frequency is given as 400 Hz, then the speed will be
Speed = wavelength × Frequency = 20 × 400
Speed of wave = 8000 m/s.
So speed of wave is 8000 m/s.
Answer:
<h3>0.445</h3>
Explanation:
In friction, the coefficient of friction formula is expressed as;

Ff is the frictional force = Wsinθ
R is the reaction = Wcosθ
Substitute inti the equation;

Given
θ = 24°

Hence the coefficient of kinetic friction between the box and the ramp is 0.445
Answer:

Explanation:
Given
-- radius of hydrogen atom
<em>See attachment</em>
Required
Determine the radius of magnesium atom (R)
From the attachment, the ratio of a hydrogen atom to a magnesium atom is:

Simplify

Represent the radius as ratio:

Substitute 

Equate both ratios

Express as fraction

Cross Multiply







Hence, the radius of the magnesium atom is: 
Answer:
Vd = 1.597 ×10⁻⁴ m/s
Explanation:
Given: A = 3.90×10⁻⁶ m², I = 6.00 A, ρ = 2.70 g/cm³
To find:
Drift Velocity Vd=?
Solution:
the formula is Vd = I/nqA (n is the number of charge per unit volume)
n = No. of electron in a mole ( Avogadro's No.) / Volume
Volume = Molar mass / density ( molar mass of Al =27 g)
V = 27 g / 2.70 g/cm³ = 10 cm³ = 1 × 10 ⁻⁵ m³
n= (6.02 × 10 ²³) / (1 × 10 ⁻⁵ m³)
n= 6.02 × 10 ²⁸
Now
Vd = (6A) / ( 6.02 × 10 ²⁸ × 1.6 × 10⁻¹⁹ C × 3.9×10⁻⁶ m²)
Vd = 1.597 ×10⁻⁴ m/s