Answer:
a. 15.4 seconds
b. 0.455 m/s
Explanation:
a. The carousel rotates at 0.13 rev/s.
This means that it takes the carousel 1 sec to make 0.13 of an entire revolution.
This means that time it will take to make a complete revolution is:
1 / 0.13 = 7.7 seconds
Therefore, the time it will take to make 2 revolutions is:
2 * 7.7 = 15.4 seconds
b. Let us calculate the linear velocity. Angular velocity is given as:

where v = linear velocity and r = radius
The radius of the circle is 3.5 m and the angular velocity is 0.13 rev/s, therefore:
0.13 = v / 3.5
v = 3.5 * 0.13 = 0.455 m/s
Linear velocity is 0.455 m/s
Solution:
With reference to Fig. 1
Let 'x' be the distance from the wall
Then for
DAC:

⇒ 
Now for the
BAC:

⇒ 
Now, differentiating w.r.t x:
![\frac{d\theta }{dx} = \frac{d}{dx}[tan^{-1} \frac{d + h}{x} - tan^{-1} \frac{d}{x}]](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5Ctheta%20%7D%7Bdx%7D%20%3D%20%5Cfrac%7Bd%7D%7Bdx%7D%5Btan%5E%7B-1%7D%20%5Cfrac%7Bd%20%2B%20h%7D%7Bx%7D%20-%20%20tan%5E%7B-1%7D%20%5Cfrac%7Bd%7D%7Bx%7D%5D)
For maximum angle,
= 0
Now,
0 = [/tex]\frac{d}{dx}[tan^{-1} \frac{d + h}{x} - tan^{-1} \frac{d}{x}][/tex]
0 = 

After solving the above eqn, we get
x = 
The observer should stand at a distance equal to x = 
Answer:
The velocity of the star is 0.532 c.
Explanation:
Given that,
Wavelength of observer = 525 nm
Wave length of source = 950 nm
We need to calculate the velocity
If the direction is from observer to star.
From Doppler effect

Put the value into the formula







Negative sign shows the star is moving toward the observer.
Hence, The velocity of the star is 0.532 c.
Answer:
c. turn downward
Explanation:
From the information given:
To find the tendency of the sander;
We need to apply the right-hand rule torque; whereby we consider the direction of the flywheel, the direction at which the torque is acting, and the movement of the sander toward the right.
Since the flywheel of the sander is in counterclockwise movement, hence the torque direction will be outward placing on the wall. However, provided that the movement of the sander is toward the right, then there exists an opposite force that turns downward which showcases the tendency in the sander is downward.
Using the Universal Gratitation Law, we have:
Again applying the formula in the new situation, comes:
Number 4If you notice any mistake in my english, please let me know, because i am not native.