Question 2. an object travels with velocity (2,3,5) m/s. (a) what is the speed of the object? (b) find a unit vector in the direction of (2,3,5), and one in the opposite direction. (c) the object slows down to speed 3 m/s without changing direction give its velocity vector.

Step-by-step explanation:

Part 1)

Since speed defined as  the magnitude of velocity vector we have

Applying values we get

Thus the speed of the object is 6.16 m/s

Part 2)

A unit vector in the direction of is given by

Applying values we get

Unit vector in direction of the given vector is

The unit vector in opposite direction is

Part 3)

Since the speed of the particle reduces to 3 m/s from 6.16 m/s this can be brought about by varying each thus the problem is indeterminate since the no. of variables is 3 ( each individual component of velocity can be changed independently) but the equation avaliable is only 1. Thus we cannot find the velocity vector only by the information given.  

step-by-step explanation:

20% of 120 is 24. if you subtract 24 from 120 you get 96

(a) the volume of the cone is 20/3 in3

hence, option a is correct.