Answer:
the wavelength is 9.8 meters
Explanation:
We can use the relationship:
Velocity = wavelenght*frequency.
Initially we have:
wavelenght = 4.9m
velocity = 9.8m/s
then:
9.8m/s = 4.9m*f
f = 9.8m/s/4.9m = 2*1/s
now, if the velocity is doubled and the frequency remains the same, we have:
2*9.8m/s = wavelenght*2*1/s
wavelenght = (2*9.8m/s)*(1/2)s = 9.8 m
the correct choice is
C) an electric current.
as a magnet is turned quickly relative to a coil, the magnetic flux linked with coil varies due to variation of angle of direction of magnetic field with normal to the plane of coil. the coil resist this change of magnetic flux in it by inducing emf in it so as to nullify the variation in magnetic flux. Due to this induced emf , electric current flows through the coil.
Answer:

cubic metre or 1e-9
Explanation:
•By division. Number of cubic millimetre divided(/) by 1000000000, equal(=): Number of cubic metre.
•By multiplication. 83 mm3(s) * 1.0E-9 = 8.3E-8 m3(s)
Answer:
C. Talk test
Explanation:
The talk test would be readily available to me at the the least cost.
The talk test is about the easiest way that one can monitor intensity as they exercise. Because the only thing needed here is the ability to talk and to breathe.
The intensity lies on if one can talk and breathe at the same time. The harder one exercises, the more breathless they become and they find it difficult to talk.
Moving a spring back and forth creates a longitudinal wave