Answer:
20 mins
Explanation:
To go 90 km it takes =60 mins(1 hr)
" " 1 km it takes =60/90 mins
" " 30 km it takes =60/90 multiplied by 30
= 20 mins
All you can say about it is that it then vibrates perpendicular to the x-axis. But that could be up and down parallel to the y-axis, in and out parallel to the z-axis, or some of it in every possible direction perpendicular to the x-axis. We "polarize" the light when we want to pick out only one perpendicular direction and stop all the others.
Suppose earth is a soid sphere which will attract the body towards its centre.So, acc. to law of gravitation force on the body will be,
F=G*m1m2/R^2
but we now that F=ma
and here accleration(a)=accleration due to gravity(g),so
force applied by earth on will also be mg
replace above F in formula by mg and solve,
F=G*mE*m/R^2 ( here mE is mass of earth and m is mass of body)
mg=G*mEm/R^2
so,
g =G*mE/R^2
I think it is d I hope this help you if not let me know if it is not right
Gravity is what holds the planets in orbit around the sun and what keeps the moon in orbit around Earth. The gravitational pull of the moon pulls the seas towards it, causing the ocean tides. Gravity creates stars and planets by pulling together the material from which they are made.