A spherical interplanetary probe of 0.5-m diameter contains electronics that dis

Here is problem, please help 

A 30.0 kg block is resting on a flat horizontal table. On topof this block is resting a 15.0 kg block, to which a horizontal spring is attached. The spring constant of the spring is 325 N/m. The coefficient of kinetic friction between the lower block and the table is 0.600, and the coefficient of static friction between the two blocks is 0.900. A horizontal force is applied to the lower block. This force is increasing in such a way as to keep the blocks moving at a constant speed. At the point where the upper block begins to slip on the lower block,determine (a) the amount by which the spring is compressed and (b) the magnitude of the force F.

Hi I need help with thisquestion. A uniform metal rod, with a mass of 3.1 kg and a length of 1.2 m,is attached to a wall by a hinge at the base. A horizontalwire bolted to the wall 0.51 m above the base of the rod holds therod at an angle of 25 degrees above the horizontal. The wireis attached to the top of the rod. (a) Find the tension inthe wire. (b) Find the horizontal and verticalcomponents of the force exerted on the rod by the hinge. Thank you

An elevator (mass 4850 kg) is to be designed so that themaximum acceleration is 0.0600g. What is the maximum and the minimum forces the motor should exert on the supportingcable?
I already know how to find the maximum force (just multiplyingthe maximum acceleration by the mass), but I've got no clue as tohow to find the minimum acceleration when no minimum accelerationhas been found.

Divide numerator and denominator by the highest power of x in the denominator and proceed from there. Find the limits
${\displaystyle \underset{x\to -\mathrm{\infty }}{lim}{\left(\frac{x^2+x-1}{8x^2-3}\right)}^{\frac{1}{3}}}$

A medical technician is trying to determine what percentage of apatient's artery is blocked by plaque. To do this, she measures theblood pressure just before the region of blockage and finds that itis ${\displaystyle 1.20\times {10}^{4}Pa}$, while in the region of blockage it is ${\displaystyle 1.15\times {10}^{4}Pa}$. Furthermore, she knows that blood flowingthrough the normal artery just before the point of blockage istraveling at 30.0 cm/s, and the specific gravity of this patient'sblood is 1.06. What percentage of the cross-sectional area of thepatient's artery is blocked by the plaque?

How do you simplify ${\displaystyle (2-3i)÷(1+5i)}$?