Answer:
12.5N
Explanation:
Data;
W = 50N
Fh = 15N
μ = 0.4
Fv= ?
The second attachment is showing the resolution of the vectors.
The normal force acting on the box (N) = W - Fv
The frictional force ( ⃗f) = Fh
Frictional force ⃗f = μN = μ(W - Fv)
μW - μFv = Fh
Fv = W - (Fh/μ)
Fv = 50 - (15/0.4) = 50 - 37.5
Fv = 12.5N
The smallest vertical force which moves the box is 12.5N
Answer:
v2 = 12m/s
Explanation:
To find the velocity of water in the lower tube you use the following formula:
(1)
v1: velocity in the first tube
v2: velocity in the second tube
A1: area of the first tube
A2: area of the second tube
From the expression (1) you can obtain the velocity v2, that is the velocity of water in the second tube:
you replace the values of the parameter in order to calculate v2:
hence, the velocity of the water is 12m/s
Answer:
35/9 m/s
Explanation:
21 km = 21000 m
90 min = 90*60 s = 5400 s
21000/5400 = 35/9 m/s
The Doppler Effect provides the equation for the
calculation of apparent frequency:
f=fo[vo/(vo-vr)]
where:<span>
vo=source wave velocity
vr=relative speed between source and observer
f=apparent frequency
fo=source frequency </span>
<span>
The velocity of the doppler wave is
v=λf</span>
where λ is light wavelength. Hence,
v=λfo[vo/(vo-vr)]
Based on the equation, we can say that wave
velocity will always be defined by one and only one wavelength.
Therefore the answer is letter C.
<span> </span>