Weak winds that blow for short periods of time with a short fetch.
Basic truss bridge types found in North Carolina (source: HAER) A truss bridge can be characterized by the location of its traffic deck. At a pony truss, the travel surface passes along the bottom chords of trusses standing to either side that are not connected to each other at the top.
Answer:
9ms^2
Explanation:
since ,Force=mass*acceleration
then, acceleration=force/mass
and, Force=90N
Mass=10pound
therefore, acceleration=90/10
=9ms^2
Where the force is not perpendicular to the path of motion
are you missing the the situations ?
Answer:
54 N
Explanation:
Draw a free body diagram. There are four forces acting on the balloon. Buoyant force pushing the balloon up, gravity pulling the helium down, gravity pulling the balloon skin down, and gravity pulling the load down.
Apply Newton's second law:
∑F = ma
B − Wh − Wb − L = ma
When the load is at a maximum, the acceleration is 0:
B − Wh − Wb − L = 0
B − Wh − Wb = L
B − mh g − Wb = L
The mass of the helium is its density times its volume:
B − ρh Vh g − Wb = L
Buoyant force is defined as B = ρVg, where ρ is the density of the displaced fluid (in this case, air), V is the volume of the displaced fluid, and g is acceleration of gravity. Since the volume of displaced air = the volume of the helium:
ρa V g − ρh V g − Wb = L
(ρa − ρh) V g − Wb = L
Given that ρa = 0.90 kg/m³, ρh = 0.178 kg/m³, V = 20 m³, g = 9.8 m/s², and Wb = 88 N:
(0.9 − 0.178) (20) (9.8) − (88) = L
L = 53.5 N
Rounded to 2 sig-figs, the maximum load that can be supported is 54 N.
