# The origin of x and y coordunates is the pole of a concave mirror of focal length 20 cm. The x axis is the optical axis with x>0 being the real side of mirror. A point object(25cm,1cm) is moving with a velocity 10 cm/sec in positive x direction. Find velocity of image?..plz help

Suhita singh
4 Points
4 years ago
1/v+1/u=1/f
for concave mirror
1/v+1/-25=1/-20
V=-100cm
Now magnification=-v/u=-(-100/-25)=-4
Now velocity of image=-m×m×velocity of object
therefore V(image)=-(-4×-4)×10=160cm/s(-x axis direction)
10 Points
4 years ago
Suhita singh
4 Points
4 years ago
Since y-axis position coordinate is not changing and their is no velocity of object in y- axis therefore velocity of image in y-axis direction is zero
10 Points
4 years ago
U is changing ..therfore height of objecy is changing...and hence there will be velocity component in vertucal direction
jon tayson
13 Points
one year ago
velocity of immage = [-160 i + 8 j ] cm/s
it means it moves with 160cm/s in negative x-direction and moves with 8cm/s in y direction .