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1) A person weighs 612 N. If this person sits in the middle of a hammock that is 3.0 m long and it sags 1.0 m below the points of support, what force would be exerted by the two hammock ropes.
a. .005 N
b. 204 N
c. 459 N
d. 918 N

2) a stone is thrown horizontally at 10 m/s from the top of a cliff 50 m high. how far from the base of the cliff will it land?
a. 3.4 m
b. 10.2 m
c. 34 m
d. 102 m

3) a soccer player kicks a ball in to the air at an anle of 32 degrees above the horizontal. the initial velocity of the ball is +26.0 m/s. how long is the soccer ball in the air?
a. 0.11 s
b. 1.4 s
c. 2.6 s
d. 2.8 s

2007-11-29 08:28:13 · 3 answers · asked by Anonymous in Science & Mathematics Physics

3 answers

the first question i think 918N , but i am not 100% positive

cuz the the person is 612N if 2 strings of each side is smaller than the person it makes string breaks a part and that person fallls down .

Tension force of each side is 459N

so the total force is 918N

but i dont know they want to ask for total force or individual force
either 459 or 918N.


2. i got 31.9m but i dont know why the answer is not on your list .


3. answer is 2.8m/s

convert v initial to Viy = 26sin32 = 13.8
Yf= yi+ViyT -4.9T^2

when they hit ground Yf=0
0 = 13.8T-4.9T^2
solve that for T
T= 2.8sec

2007-11-29 08:52:31 · answer #1 · answered by Helper 6 · 0 0

1) The hammock ropes do not stretch, so the angle at the supports below the horizontal is
sin(th)=1/1.5

and summing forces in the vertical
2*sin(th)*T=612
where T is the tension
T=459 N
Waddya know, it is C.

2 The equations of motion are
x(t)=10*t
and y(t)=-.5*g*t^2

when y(t)=-50, the stone strikes the ground
solve for t
t=sqrt(100/9.81)
t=3.16
so x(3.16)=31.6
I guess C is the closest.

3. the total flight time is twice the time to apogee
at apogee vy(t)=0
vy(t)=26*sin(32)-g*t
solve for t

the flight time is d, 2.8 seconds using
g=9.81



j

2007-11-29 08:52:38 · answer #2 · answered by odu83 7 · 0 0

They always say if you dont know the answer, pick "C"

2007-11-29 08:36:41 · answer #3 · answered by bsabs1825 1 · 0 0

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