Answer:
[tex]\theta=28.07^{\circ}[/tex]
Explanation:
Speed of van, v = 28 m/s
Radius of unbanked curve, r = 150 m
Let [tex]\theta[/tex] is the angle with the vertical. In case of banking of road,
[tex]T\ cos\theta=mg[/tex].............(1)
And
[tex]T\ sin\theta=\dfrac{mv^2}{r}[/tex]..........(2)
From equation (1) and (2) :
[tex]tan\theta=\dfrac{v^2}{rg}[/tex]
[tex]tan\theta=\dfrac{(28)^2}{150\times 9.8}[/tex]
[tex]\theta=28.07^{\circ}[/tex]
So, the string makes an angle of 28.07 degrees with the vertical. Hence, this is the required solution.