Question 93: Laws of Motion

Question

A block 'A' takes 2 s to slide down a frictionless incline of 30$$^\circ$$ and length 'l', kept inside a lift going up with uniform velocity 'v'. If the incline is changed to 45$$^\circ$$, the time taken by the block, to slide down the incline, will be approximately :

Accepted Answer

$${	heta _1} = 30^\circ ,\,{	heta _2} = 45^\circ $$
$${a_1} = g\sin {	heta _1} = 5$$ m/s
2
, $${a_2} = g\sin {	heta _2} = 5\sqrt 2 $$ m/s
2
$${{{t_1}} \over {{t_2}}} = {{\sqrt {{{2l} \over {{a_1}}}} } \over {\sqrt {{{2l} \over {{a_2}}}} }} = \sqrt {{{{a_2}} \over {{a_1}}}} $$
$${{{t_1}} \over {{t_2}}} = {(2)^{1/4}}$$
$${t_2} = {(2)^{3/4}}$$
$$ \approx 1.68$$ s

Answer

2.66 s

Answer

0.83 s

Answer

1.68 s

Answer

0.70 s

Laws of Motion

A block 'A' takes 2 s to slide down a frictionless incline of 30$^\circ and length 'l', kept inside a lift going up with uniform velocity 'v'. If the incline is changed to 45^\circ$, the time taken by the block, to slide down the incline, will be approximately :

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