Answer:
A model rocket is launched with an initial upward velocity of 215 ft/s.
Explanation:
' W ' is the symbol for 'Watt' ... the unit of power equal to 1 joule/second.
That's all the physics we need to know to answer this question.
The rest is just arithmetic.
(60 joules/sec) · (30 days) · (8 hours/day) · (3600 sec/hour)
= (60 · 30 · 8 · 3600) (joule · day · hour · sec) / (sec · day · hour)
= 51,840,000 joules
__________________________________
Wait a minute ! Hold up ! Hee haw ! Whoa !
Excuse me. That will never do.
I see they want the answer in units of kilowatt-hours (kWh).
In that case, it's
(60 watts) · (30 days) · (8 hours/day) · (1 kW/1,000 watts)
= (60 · 30 · 8 · 1 / 1,000) (watt · day · hour · kW / day · watt)
= 14.4 kW·hour
Rounded to the nearest whole number:
14 kWh
Answer:
2,4
Explanation:
LOL WHERE THE PICTURE GURL?
Answer:
Yes.
Explanation: the magnitude of the force is extremely small because the masses of the students are small relative to Earth's mass.
a) In this case the forces are the centrifugal force Fcp,
which is directed horizontally toward the wall; the force of static friction Ff
with the wall, directed upward; the normal force Fn by the wall, which is
directed away the wall; the force of gravity Fg, directed downwards. Then we
have that the horizontal forces are all equal in magnitude; similarly the
vertical forces are also all equal in magnitude.
b) The minimum coefficient s occurs when force of gravity
is equals the max friction force, that is
Fg = Ff,max
m g = s Fn
Also, the normal force has equal magnitude to the
centrifugal force:
m g = s Fcp
m g = s m w^2 r
g = s w^2 r
s = g / (r w^2)
With values: g = 9.81 m/s^2; r = 2.5 m; and w = 2pi *
0.60 = 3.77 rad/s; we find
s = 9.81 / (2.5 * 3.77^2) = 0.276
