Asubmarine at the surface dives 375 ft and then another 175 ft. express the final depth as an integer.
a. –525 ft
b. –550 ft
c. 550 ft
d. 525 ft

Hello mate!

If we consider y = 0ft in the surface (the initial position of the submarine)

When the submarine does the first dive, it descends 375ft

then the position is y = 0ft - 375ft = -375ft

where the position is negative because the submarine is descending.

Now, the submarine decends another 175ft, so the new position is:

y = -375ft - 175ft = -550ft

i have no clue at all sorry

step-by-step explanation:

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12