Answer:
The number of turns, N = 1750
Explanation:
It is given that,
The inner radius of a toroid, r = 12 cm
Outer radius, r' = 15 cm
The magnetic field at points within the coils 14 cm from its center is, 
R = 14 cm = 0.14 m
Current, I = 1.5 A
The formula for the magnetic field at some distance from its center is given by :



N = 1750
So, the number of turns must have in a toroidal solenoid is 1750. Hence, this is the required solution.
The third choice.
The driver wants to see the object that is behind him. The light reflects off the mirror into the eyes of the driver portraying the object behind him
The lenses on a camera focus the light entering the camera and provide a clear, sharp image at the location of the film or CCD device. If you took the lenses off a camera designed for use with lenses, you would not be able to create a usable image.
Refer to the diagram shown below.
We want to find y in terms of d, φ and θ.
By definition,

Therefore
y = x tan(θ) (1)
y = (x - d) tan(φ) (2)
Equate (1) and (2).
![(x - d) \, tan(\phi) = x \, tan(\theta) \\ x[tan(\phi) - tan(\theta)] = d \, tan(\phi) \\ x= \frac{d tan(\phi)}{tan(\phi)-tan(\theta)}](https://tex.z-dn.net/?f=%28x%20-%20d%29%20%5C%2C%20tan%28%5Cphi%29%20%3D%20x%20%5C%2C%20tan%28%5Ctheta%29%20%5C%5C%20x%5Btan%28%5Cphi%29%20-%20tan%28%5Ctheta%29%5D%20%3D%20d%20%5C%2C%20tan%28%5Cphi%29%20%5C%5C%20x%3D%20%5Cfrac%7Bd%20tan%28%5Cphi%29%7D%7Btan%28%5Cphi%29-tan%28%5Ctheta%29%7D%20)
From (1), obtain the required expression for y.
Answer:
1) If the object changes directions with the same speed, it will be changing its velocity, because velocity is a vector, which depends on both magnitude and direction. Speed is just magnitude regardless of direction.
2) Rotational motion.