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An object moving at a speed of 5 m/s towards a concave mirror of local length f = 1 m is at a distance of 9 m. The average speed of the image is : |
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Answer» `(1)/(5) m//s` `(1)/(V) + (1)/(u) = (1)/(f) or v = (fu)/(u-f)` When an object is at a distance of 9 m from the concave mirror `thereforeu=-9m,f=-1mrArrV=((-1)(-9))/(-9+1)=-(9)/(8)m` As the object moves at a constant SPEED of `5ms^(-1)`, after 1s the position of image is `u.=-9m+5m=-4mrArr V. = ((-1)(-4))/(-4+1)=-(4)/(3)m` The shift in the position of image in 1 s is `V-V.=(-9)/(8)+(4)/(3)=(-27+32)/(24)=(5)/(24)=(1)/(4.8)APPROX(1)/(5)` Average speed of the image `= (1)/(5) ms^(-1)`. |
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