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

What should be the minimum force $P$ to be applied to the string so that a block of mass $M$ just begins to move up the frictionless inclined plane? The string passes over a pulley attached to the block,with one end fixed to the incline and the other pulled with force $P$ at an angle $\theta$ with the incline.

$A$ truck of mass $10,000\, kg$ moves up an inclined plane rising $1$ in $50$ with a speed of $36\, km/h$. Find the power of the engine in $kW$ $(g = 10\, m/s^2)$.

$A$ block of mass $m$ is placed on a smooth fixed inclined plane with an angle of inclination of $37^{\circ}$. $A$ horizontal force $F$ is applied to keep the block at rest. Find the value of $F$.

$A$ 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 $........\,s$.

$A$ smooth inclined plane is inclined at an angle $\theta$ with the horizontal. $A$ body starts from rest and slides down the inclined surface. The time taken by it to reach the bottom is