WAEC - Physics (1996 - No. 27)
A boy walks away from a plane mirror at a speed of 3 ms-1 in a direction normal to the surface of the mirror. At what speed is his image approaching him?
8 9.0ms-1
6.0ms-1
4.5ms-1
1.5ms-1
0.0ms-1
คำอธิบาย
Velocity of image w.r.t boy = velocity of object - velocity of image
velocity w.r.t to boy = v - (-v)
=3.0 - (-3.0)
The image velocity is 6 m/s towards the boy.