Answer:
B) 41,335 N
Explanation:
As the elevator moves upward the formula for the calculation of tension in the cable is given by.
T-mg =ma
T=mg+ma
T=3500*9.81+3500*2
=34335+7000
T=41,335 N
-- The overall <em>distance</em> he travels is (100m + 30m + 70m) = <em>200 meters</em>.
-- His <em>displacement </em>when he arrives at his front door is
D = (100m East) + (30m West) + (70m East)
D = (100m + 70m)East + (30m)West
D = (170m East) + (30m West)
<em>D = 140 meters East </em>
It's interesting to notice that his displacement is 60 meters shorter than the distance he walked.
That's because there's a stretch of 30 meters somewhere in the middle that he actually covered <em>three times</em>.
Two of those times added to the distance his shoes covered (2x30m=60m), but they cancelled out of the displacement.
His front door is 140 meters East of school. He walked 60m farther than that, going back and forth over the 30m piece.
Box has all sides same leinght(a). Area of that box is 6*a^2.
Cost of material for bottom and 4 sides is 2$/ft^2. Area of bottom and sides is A=5*a^2
Cost of material for top is 4$/ft^2. Area of top of the box is T=a^2
A*2+T*4=72
5*a^2*2+a^2*4=72
a^2*(10+4)=72
a^2*14=72, a^2=72/14, a=root(72/14), a=2.267ft
Dimensions of the box: leinght of sides 2.2ft. Area of hole box 30.835ft^2
Area of the bottom and sides: A=5*a^2=25.696ft^2
Area of the top : T=a^2=5.139ft^2
Check: A*2$+T*4$=71.95$
They belong to the kingdom of Chordata
