Answer:
the angle of incident is 40°
Explanation:
NQ is the normal to the mirror, therefore
angle NQA =90°
PQA = 50°
incident angle = NQA - PQA
90°- 50° = 40°
note that the angle of reflection is equal to the angle of incident
Answer:
The position of the spring in terms of g, m & k is
Explanation:
Stiffness of the spring = k
Mass = m
When a mass m is attached with the spring then spring stretched. in that case the force exerted on the spring is equal to weight of the mass attached.
⇒ Force exerted on the spring F = k x
⇒ m g = k x
⇒
This is the position of the spring in terms of g, m & k.
The correct answer is: <span>X, W, Y, Z
In fact, the elastic potential energy of a spring is given by
</span>
<span>where k is the spring constant and x is the stretching of the spring with respect to its rest position.
In this problem, all the four springs are stretched by the same distance x. This means that their difference in potential energy is due only to the difference between their spring constant: the larger the spring constant, the greater the energy. Therefore we can list the springs from the one with largest spring constant to the one with smallest constant, and this list corresponds to listing the springs from the one with largest energy to the one with smallest energy:
X, W, Y, Z</span>
<span>Answer:
The moments of inertia are listed on p. 223, and a uniform cylinder through its center is:
I = 1/2mr2
so
I = 1/2(4.80 kg)(.0710 m)2 = 0.0120984 kgm2
Since there is a frictional torque of 1.20 Nm, we can use the angular equivalent of F = ma to find the angular deceleration:
t = Ia
-1.20 Nm = (0.0120984 kgm2)a
a = -99.19 rad/s/s
Now we have a kinematics question to solve:
wo = (10,000 Revolutions/Minute)(2p radians/revolution)(1 minute/60 sec) = 1047.2 rad/s
w = 0
a = -99.19 rad/s/s
Let's find the time first:
w = wo + at : wo = 1047.2 rad/s; w = 0 rad/s; a = -99.19 rad/s/s
t = 10.558 s = 10.6 s
And the displacement (Angular)
Now the formula I want to use is only in the formula packet in its linear form, but it works just as well in angular form
s = (u+v)t/2
Which is
q = (wo+w)t/2 : wo = 1047.2 rad/s; w = 0 rad/s; t = 10.558 s
q = (125.7 rad/s+418.9 rad/s)(3.5 s)/2 = 952.9 radians
But the problem wanted revolutions, so let's change the units:
q = (5528.075087 radians)(revolution/2p radians) = 880. revolutions</span>