Question

A trolley car slides down a smooth inclined plane of angle of inclination $\theta$. If a body is suspended from the roof of the trolley car by an inextensible string of length l, the corresponding tension in the string will be

• A. mg
• B. mg cos$\theta$
• C. mg sin$\theta$
• D. None of these

Answer 1

The correct option is B mg cos$\theta$


Let tension in string be ${}^{\prime }{T}^{\prime }$ and block of mass m be sliding down an inclined plane with an angle of inclination $\theta$ .
Since acceleration is along the plane, applying condition of equilibrium perpendicular to plane,
$T-mgcos\theta =0$
$T=mgcos\theta$