Q: A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. A plumb bob is suspended from the roof of the car by a light rod. The angle made by the rod with the vertical is (Take g=10 m/s2)
(a)Zero
(b)30°
(c)45°
(d)60°
Click to See Answer :
Ans: (c)
Sol: Draw FBD of bob
$\large T cos\theta = mg$
$\large T sin\theta = \frac{m v^2}{r}$
on dividing,
$\large tan\theta = \frac{v^2}{r g} = \frac{(10)^2}{10\times 10}$
tanθ = 1
θ = 45°