1.

An elevator whose floor-to-ceiling destance is 2.50 m starts ascending with a constant acceleration of 1.25 ms^(-2) On second after the start, a bolt begins falling from the elevator. Calculate: a. The free fall time of the bolt b. The displacement and reference frame of ground.

Answer»


Solution :a. ` t=sqrt((2h)/(g+a))=sqrt((2xx2.5)/(10+1.25))=(2)/(3) s `
B. Velocity of LIFT after `1` s.
`v=0 +1.25 xx 1=1.25 ms^(-1) =5//4 ms^(-1)`
Ths will be the initial velocity of bolt.
Destance moved up by lift in `2//3 s`,
` x=(5)/(4)xx(20/(3)+(1)/(2)1.25((2)/(3))^(2)=(10)/(9)m`
Displacement of bolt `=2.5-x=2.5 -(10)/(9) =(25)/(18) m`
Maximum height attained by bolt above the point of dropping ,
`(v^(2))/(2g)=((5//4)^(2))/(2xx 10) =(5)/(64) m`
So distance travelled=`2xx (5)/(64)+ (25)/(18)=(445)/(288)m`.


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