laws of motion Questions

Two masses $m_1=5\text{kg}$ and $m_2=4.8\text{kg}$ tied to a string are hanging over a light frictionless pulley. What is the acceleration of the masses when left free to move? (Take $g=9.8{\text{m/s}}^2$)

A block rests on a rough inclined plane making an angle of $30^{\circ }$ with the horizontal. The coefficient of static friction between the block and the plane is $0.8$. If the frictional force on the block is $10\text{N}$, the mass of the block (in kg) is: (take $g=10{\text{m/s}}^2$)