A balloon is moving up in the air vertically above point A on the ground. When it is at a height , a girl standing at a distance (point
) from
(see figure) sees it at an angle
with respect to the vertical. When the balloon climbs up a further height
, it is seen at an angle
with respect to the vertical if the girl moves further by a distance
(point
). Then the height
is (given
) :
A helicopter rises from rest on the ground vertically upwards with a constant acceleration . A food packet is dropped from the helicopter when it is at a height of h. The time taken by the packet to reach the ground is close to [
is the acceleration due to gravity ]:
The sum of two forces and
is
such that
The angle
(in degrees) that the resultant of
and
will make with
is ,