Question

a stone is dropped from the edge of a roof h=49m it passes a window 2m high in 1 sec. how far is the roof above the top of window

Answer 1

47m is the answer because total height till roof is 49m and the height of window is 2m so the distance between roof and window is 47m

Answer 2

of the window (h) = 2mAcceleration due to gravity g = 9.8 m/s2Time taken (t) = 0.1 sThe velocity of the stone when it reaches the top of the window is to be calculated.Applying the II equation of motion,h=ut+1/2 at^22=0.1u+0.0490.1u=1.951u= 19.51m/sThus, the velocity 19.51 m/s will be the final velocity of the stone when it is covering the distance between the roof and the window.Initially the stone is at rest i.e., u = 0v^2-u^2=2gh(19.51)^2=19.6h=> h= 19.42mDistance between the roof and the window =19.42 m.5 years agolet the distance between roof and wndow be x metresthen time taken to reach it be tthen x=1/2.g.t^2..........................(1)for .1 secs more than time t,it covers  (x+5) metreshence x+5=1/2.g.(t+.1)^2x + 5 = 1/2.g.t^2 + 1/2.g.(.1)^2  + g.t.(.1)               { by expanding RHS}x + 5 =    x         +     1/20         +    t                     {from eq(1),and putting g=10}5 - .05 = tt=4.95 secshence the stone takes 4.95 sec to reach the window from the roofso required distance=x=1/2.g.t^2                  (from eq(1) )x=122.5 metres (ANS)hope i helped you.5 years agoUsing second eqn of motion we get:s=0.5gt2s=5(0.01)=0.05m5 years ago19.0125 m5 years ago5 years agoi am sorry .i made a mistake.for .1 sec. it covers 2 m.hence  x+2=x+1/20+tt=1.95 sechence x=1/2.g.t^2x=19.01 m(ANS)5 years ago0.98M IF U=05 years agoThink You Can Provide ABetter Answer ?Answer & Earn Cool Goodies

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