Yeah yeah I just got a hold of you and I saw that you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job and I thought you were doing a good job.
If I remember correctly (from my studies long time ago) the layers are from the outer to the center:
SiAl : Silicon-Aluminum
SiMa : Silicon-Magnesium (although should be Mg)
NiFe : Nickel-Iron
The SiMa layer should have the lightest elements (Magnesium is lighter than Aluminum)
The Sun's gravitational pull keeps our planet orbiting the Sun <span>in a nice nearly-circular orbit.</span>
The sum of potential energy<span> and kinetic </span><span>energy.
Hope I helped!</span>
Answer:
Electric field, 
Explanation:
It is given that,
Mass of sphere, m = 2.1 g = 0.0021 kg
Charge, 
We need to find the magnitude of electric field that balances the weight of a plastic spheres. So,

a = g



or

Hence, the magnitude of electric field that balances its weight is
. Hence, this is the required solution.