When a plane minor is placed horizontally on level ground at a distance of om from the foot of tower the top of the tower and its image in the mirror subtend an angle of 90" at the eye. The height of the tower
a) 30m
b) 60m
c) 90 m
d) 120m

b : 60m

Explanation:

when a plane mirror is placed horizontally on a level ground at a distance of 60m from the top of tower as shown in figure. a/c to question, The top of tower and its image in the mirror subtend an angle of 90° at the eyes. so, angle made by top of tower and horizontal line is 45° as

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.