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)
TRUE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
The work could be either positive or negative, depending on the direction the object moves
Explanation:
Acceleration (magnitude anyway) = (change in speed) / (time for the change) .
Change in speed = (10 - 30) = -20 m/s
Time for the change = 4.0sec
Magnitude of acceleration = -20/4 = <em>-5 m/s² </em>