Question

A ball is suspended by a thread from the ceiling of a tram car. The brakes are applied and the speed of the car changes uniformly from $36 \, Km \, h^{- 1}$ to zero in $5 \, s$ . The angle by which the ball deviates from the vertical is $\left(g = 10 \, m \, s^{- 2}\right)$

• A. $\tan ^{-1}\left(\frac{1}{3}\right)$
• B. $\sin ^{-1}\left(\frac{1}{5}\right)$
• C. $\tan ^{-1}\left(\frac{1}{5}\right)$
• D. $\cot ^{-1}\left(\frac{1}{3}\right)$

Answer 1

Answer: (C)

$u=36kmh^{- 1}=10ms^{- 1}$ $v=u+at$ , $tan \theta =\frac{a}{g}$
$v=10-a\times 5\left(\right.given,v=0\left.\right)$
$a = 2$
$tan \theta =\frac{2}{10}$