The Earth's magnetic equator passes through Jos in Nigeria. At Jos, the
angle of variation is zero
magnetic declination is 90
angle of dip is zero
horizontal component at the Earth's field is zero
Correct answer is C
- angle of dip is zero at the magnetic equator
- angle of variation is the same as angle of declination.
Calculate the velocity ratio of a screw jack of pitch 0.2cm if the length of the tommy bar is 23cm
230π
23π
70π
140π
Correct answer is A
P = 0.2cm, L = r = 23cm
VR | = | 2πr
P |
= | 2πL
P |
= | 2π×23
0.2 |
= | 230π |