Get Answers to all your Questions

header-bg qa

Two inclined planes are placed as shown in figure. A block is projected from the Point \mathrm{A} of inclined plane \mathrm{AB} along its surface with a velocity just sufficient to carry it to the top Point \mathrm{B} at a height 10 \mathrm{~m}. After reaching the Point \mathrm{B} the block slides down on inclined plane \mathrm{B C}. Time it takes to reach to the point \mathrm{C} from point \mathrm{A} is \mathrm{t(\sqrt{2}+1) s}. The value of \mathrm{t} is _____________         (use \mathrm{g=10 \mathrm{~m} / \mathrm{s}^{2}} )

Option: 1

2s


Option: 2

-


Option: 3

--


Option: 4

-


Answers (1)

best_answer

For journey from A to B,

\mathrm{V_B^2=V_A^2+2 a S_1 }

\mathrm{0=V_A^2+2\left(-g \sin 45^{\circ}\right) \times \frac{10}{ \sin 45^{\circ}} }

\mathrm{V_A=10 \sqrt{2} \mathrm{~m} / \mathrm{s} }

\mathrm{V_B=V_A+a t }

\mathrm{0=10 \sqrt{2}+\left(-g \sin 45^{\circ}\right) t_1 }

\mathrm{t_1=2s}

For journey from B to C

\mathrm{S =u t_2+\frac{1}{2} a t_2^2 }

\mathrm{\frac{10}{\sin 30^{\circ}} =\frac{1}{2} \times g \sin 30^{\circ} t_2^2 }

\mathrm{t^2 _{2}=8 }

\mathrm{t_2 =2 \sqrt{2} s }

\mathrm{\text { Total time } =t_1+t_2 }

                       \mathrm{=2+2 \sqrt{2} }

\mathrm{t=2 s}   

Posted by

Gautam harsolia

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE