All the statements can be used to explain about Earth's magnetic field.
Earth's magnetic field is almost same to that of the bar magnet. The magnetic field of the earth occurs from its core. It has an inner core which is solid in nature. in the outer core, there is a motion of the liquid due to heat flow from the inner core to the core mantle boundary which proves that the outer core is liquid and moving. The Earth's core consists of iron and nickel as the Eddy currents in the iron and nickel liquid helps generating the Earth's magnetic field.
Hence, all the three statements are true and can be used to explain the Earth's magnetic field.
We know that According to Ohm's Law :
Current passing through a Conductor is directly proportional to the Voltage over a given Resistance.
⇒ V ∝ I
⇒ V = I × R
If Resistance is not changed and Voltage is increased, Based on Ohm's law we can conclude that Current flowing will also increase, because Voltage is directly proportional to Current.
Answer: vf = 51 m/s
d = 112 m
Explanation: Solution attached:
To find vf we use acceleration equation:
a = vf - vi / t
Derive to find vf
vf = at + vi
Substitute the values
vf = 3.5 m/s² ( 8.0 s) + 23 m/s
= 51 m/s
To solve for distance we use
d = (∆v)² / 2a
= (51 m/s - 23 m/s )² / 2 ( 3.5 m/s²)
= (28 m/s)² / 7 m/s²
= 784 m/s / 7 m/s²
= 112 m