The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40, then the value of W is?

giftmartins

7 years ago

Efficiency = Work input/work out put

%E = M.A/V.R *100

in the quest above Efficiency = 40% Load = 120N Effort = WN

M.A = Load/Effort
M.A =120/W
V.R = 6 (Number of Pulleys)

therefore

40 = 120/W/6*100

40 = 120/w * 1/6 * 100

40 = 20/W * 100

W = 20/40 * 100

W = 0.5 * 100

W = 50N

ShyDidi

1 year ago

wow, repeated jamb question. 1989 and 2018

Emmykah

7 years ago

V.R=6, Load=120N
efficiency=M.A*1/V.R*100%
40=120/effort*1/6*100
Effort=50N

Davidis17

5 months ago

pls i don't understand someone should explain

Sensei

2 months ago

option D is very correct 💯

Abdulmalikyar1

7 years ago

simplify it just 120N/40EF/6V.R*100=50

Kwhyn

5 years ago

I can't have access to the explanation,why

giftmartins

7 years ago

the oxidation number of nitrogen in Pb(No3)2

Remember that the valancy of Pb= +2 O=-2

Pb(No3)2=0

2+(N+(-2*3))2 = 0

2+N2+(-6*2=0

2+N2+(-12) = 0

2+N2-12=0
COLLECTING LIKE TERMS

N2=12-2
N2=10
N=10/2
N = 5
Therefore the oxidation state of nigrogen in lead (II) nitrate is +5

Kwhyn

5 years ago

There's no explanation,and I can't access the video lessons,why

ItodoQueen

4 years ago

No explanation

myfathermyfather

7 years ago

Pls show solving la