Why are mountain roads generally made winding upwards rather than going straight up?

What is the normal force on a body of mass $m$ placed on an inclined plane of angle $\theta$?

$A$ block '$A$' takes $2\,s$ to slide down a frictionless incline of $30^{\circ}$ and length '$l$',kept inside a lift going up with uniform velocity '$v$'. If the incline is changed to $45^{\circ}$,the time taken by the block to slide down the incline will be approximately $........\,s$.

As shown in the figure,an iron block $A$ of volume $0.25 \ m^3$ is attached to a spring $S$ of unstretched length $1.0 \ m$ and hanging from the ceiling. The spring gets stretched by $0.2 \ m$. This block is removed and another iron block $B$ of volume $0.75 \ m^3$ is now attached to the same spring and kept on a frictionless inclined plane of $30^{\circ}$ inclination. The distance of the block from the top along the incline at equilibrium is (in $m$)

If $M_1 = M_2 = 5 \, kg$ and $\theta = 30^\circ$,then the tension in the string will be ........... $N$.

$A$ solid sphere,a hollow sphere,and a ring are released from the top of a frictionless inclined plane,causing them to slide down the plane. For which object is the acceleration down the plane the maximum?