Answer:
B. t = 0.250s
Explanation:
A. An image with the sketch of the bat emitting a sound, which reflects on a surface and return to the bat is attached below.
B. In order to calculate the time that the pulse emitted by the bat, return to the bat, you first calculate the time that pulse takes to arrive to the object.
You use the following formula:
(1)
x: distance to the object = 43m
t: time = ?
v: speed of sound beat = 343 m/s
You solve the equation (1) for t:

The time on which the bat hears the echo is twice the value of t, that is:

The time on which bat heart the echo of its sound, from the moment on which bat emitted it, is 0.250s
The focal length of the lens is the distance between the lens and the image sensor when the subject is in focus, usually stated in millimeters (e.g., 28 mm, 50 mm, or 100 mm). In the case of zoom lenses, both the minimum and maximum focal lengths are stated, for example 18–55 mm.
Answer:
The net torque on the square plate is 2.72 N-m.
Explanation:
Given that,
Side = 0.2 m
Force 
Force 
Force 
We need to calculate the torque due to force F₁
Using formula of torque


Put the value into the formula


We need to calculate the torque due to force F₂
Using formula of torque


Put the value into the formula


We need to calculate the torque due to force F₃
Using formula of torque


Put the value into the formula


We need to calculate the net torque on the square plate



Hence, The net torque on the square plate is 2.72 N-m.
Metals, especially iron, have this form of electron cloud around it. When it's placed in a magnetic field these electrons line up