Given that: r= 1000m, \ heta=45^{0}, \\mu=0.5, m=2000kg We know that maximum safe velocity for a banked is given by : v=\\sqrt{ \\dfrac{rg ( \ an \ heta+\\mu)}{1- \\mu tan \ heta}} hence on putting the given values, we get v=\\sqrt{\\dfrac{1000 \ imes9.8 \ imes(\ an45 +0.5)}{1- 0.5\ an45}} or v=172m/s hence option A is correct