Since you're walking opposite to the motion of the walkway, the speed
that you walk subtracts from the speed of the belt. Relative to the ground
(the floor of the building), your speed is
(3.4 m/s - 1.5 m/s) = 1.9 m/s
To cover the 84-m length of the walkway, it takes you
(84 m) / (1.9 m/s) = 44.2 seconds .
If you had just stood still and gone with the flow, it would have taken
(84 m) / (3.4 m/s) = 24.7 seconds .
Whereas, if you were willing to put forth the extra effort to keep
walking on the walkway, and had walked forward instead of
backward, then you would have moved at (3.4 + 1.5) = 4.9 m/s
relative to the stationary floor, and you would have covered the
full length of the walkway in only
(84 m) / (4.9 m/s) = 17.1 seconds .
In other words, once you jumped onto the walkway, you had
three options:
-- Stand still, for 24.7 seconds;
-- Walk forward, save 7.6 seconds;
-- Walk backwards, lose 19.5 seconds !
Being in a hurry, your decision to walk backwards was the worst choice.
It was not only totally inexplicable, but it also most likely irritated the other
people on the walkway, as they met you and had to all scrunch to one side
to let you go by in reverse.
It's not surprising that you had to hurry to catch your flight, I'm guessing
that you often miss them.
Answer is Option C Lumen.It is also known as luminous energy.
Answer:
a) 202.7 N
b) 58.1 N
c) 74.1º N of E.
d) 210.9 N
Explanation:
a)
- The net force exerted in the y-direction, will be the sum of FH (which is directed northwards) and the y-component of FA.
- Since the magnitude of FA is 155 N and the angle of FA with the y-axis, is 22º (E of N), we can find the N-S component of FA, just applying the the definition of cosine, to the triangle defined by FA, the y- axis and a segment parallel to the x- axis between FA and the y-axis, as follows:
⇒ Fy = FH + FAy = 59 N + 143.7 N = 202.7 N (2)
b)
- We can proceed exactly in the same way for the x-axis.
- Since FH is directed due North, it has no component along the x-axis.
- So, Fx is directly the component of FA along the x-axis, which can be found applying the definition of sine to the same triangle than in a) as follows:
c)
- Taking the same triangle than in a) and b), we can apply the definition of tangent, in order to find the angle between F and the x-axis, as follows:
⇒ θ = tg⁻¹ (3.5) = 74.1º N of E. (5)
d)
- In order to be equal and opposite to the combined force FH+FA, it must have the same magnitude.
- This magnitude can be found applying the Pythagorean Theorem to the same triangle that we used in a), b) and c):
Answer:
F = 13.08 N
Explanation:
given,
mass of spreader = 10.9 Kg
angle made with angle = 45.3°
accelerate the spreader to 1.35 m/s in 1.6 s.
Acceleration =
=
= 0.844 m/s²
momentum in = momentum out
F × t = m × v
F×1.125 = 14.175
F = 13.08 N
hence, the force applied by the joe is equal to F = 13.08 N