a plane mirror and an object approach each other with speeds of 5 metre per second and 10 M per second respectively the speed of the image will be...
Answers
Man's speed = 30 m/s
Explanation:
Let's assume that the distance of the man from the mirror is D. The image will be at a distance D behind the mirror. Distance between the man and the image is 2D.
After one secondm the man moves a distance of 5 m/s toward the mirror.
The image also moves a distance 10 m/s toward the mirror.
Distance between the man and the image is (2D – 30)
In one second the distance between the man and image has reduced by an amount = 2D – (2D –30) = 30 m.
Thus the man’s speed toward the image is 30 m/s.
Answer:
25
Explanation:
Speed of object,
u
o
=
5
m
s
−
1
Speed of mirror,
u
m
=
10
m
s
−
1
Mirror and object are approaching each other.
To find:
Speed of image
Procedure:
Let initial position of object be at
x
o
i
=
0
Let initial position of mirror be at
x
m
i
=
u
Object distance equals the image distance. Hence, initial position of image is
x
i
i
=
2
u
Distance is the product of speed and time.
After time
t
,
Position of object will be:
x
o
f
=
x
o
i
+
u
o
t
=
5
t
Position of mirror will be:
x
m
f
=
x
m
i
−
u
f
t
=
u
−
10
t
Let the final position of image be
x
i
f
Using object distance equals image distance after time
t
.
x
i
f
−
x
m
f
=
x
m
f
−
x
o
f
x
i
f
=
2
u
−
25
t
Distance moved by image in time
t
is:
s
i
=
x
i
f
−
x
i
i
s
i
=
−
25
t
Speed is the ratio of distance and time. Speed of the image is:
v
i
=
s
i
t
=
−
25
Negative sign appears because image is moving leftwards.
Hence, speed of image is
25
m
s
−
1