The average speed is 8 miles
Answer:
magnitude of the magnetic field 0.692 T
Explanation:
given data
rectangular dimensions = 2.80 cm by 3.20 cm
angle of 30.0°
produce a flux Ф = 3.10 × 
Wb
solution
we take here rectangular side a and b as a = 2.80 cm and b = 3.20 cm
and here angle between magnitude field and area will be ∅ = 90 - 30
∅ = 60°
and flux is express as
flux Ф = 
.................1
and Ф = BA cos∅ ............2
so B = 
and we know
A = ab
so
B = 
..............3
put here value
B = 
solve we get
B = 0.692 T
Answer: 60m/s
Explanation:
The wavespeed is the distance covered by the wave in one second. It is measured in metre per second, and represented by the symbol V
Wavespeed (V) = Frequency F x wavelength λ
i.e V = F λ
In the first case:
Wavespeed = 30 m/s
Frequency of sound = 6Hz
Wavelength = 5m
In the second case:
Wavespeed = ?
Frequency of sound = (2x 6Hz = 12Hz)
Wavelength = 5m (remains constant)
Apply V = F λ
Wavespeed = 12 Hz x 5m
Wavespeed = 60m/s
Therefore, when frequency is doubled, the speed is also doubled. Thus, the new speed of the wave is 60m/s
In a block and tackle, some friction in the pulleys will reduce the mechanical advantage of the machine. To include friction in a calculation of the mechanical advantage of a block and tackle, divide the weight of the object being lifted by the weight necessary to lift it.
Hope this helps
