The equation of motion of a point in space is x = 2t, y = – 4t, z = 4t where t measured in hours and the
co-ordinates of moving point in kilometers, then the distance of the point from the starting point O (0, 0, 0) in 10 hours is :
20 km
40 km
60 km
55 km
Distance formula -
The distance between two points is =
- wherein
= -
Position of pt. after t hours is (2t, – 4t, 4t)
Position of pt. after 10 hours is (20, – 40, 40)
Distance from origin
=
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