D: a force equal to the force
Answer:
12m
Explanation:
To obtain the answer to the question given, we must observe the characteristics of image formed by a plane mirror.
The image formed by a plane mirror have the following characteristics:
1. Laterally inverted.
2. Same distance as the object from the mirror.
3. Same height as the object.
4. Virtual.
With the above information, we can calculate the distance between the boy and his image as follow:
Initially:
Object distance (u) = 4m
Image distance (v) = 4m
The boy moved 2m away, therefore:
Object distance (u) = 2 + 4 = 6m
Image distanc(v) = 2 + 4 = 6m
The distance between the boy and his image will be the sum of his distance (u) and image distance (v) i.e (u + v)
The distance between the boy and his image = 6 + 6 = 12m
Therefore, the distance between the boy and his image is 12m.
Answer:
150000000000 m
0.0000005 seconds
33.33 ns
Explanation:
Speed of electromagnetic waves through vacuum = 
Echo time = 1000 seconds
Echo time is the time taken to reach the object and come back to the observer
Distance = Speed×Time
Venus is 150000000000 m away from Earth
Time = Distance / Speed
Echo time will be twice the time
The echo time will be 0.0000005 seconds
Difference in time = Difference in distance / Speed
The accuracy by which I will be able to measure the echo time is 33.33 ns
Seven
The magnitude is pointing towards the origin and is at - 20 degrees. The combination makes 160 with the x axis: C answer
Eight
They keep doing this. They use distance where they should use displacement but they use distance to try and fool you. It's a mighty poor practice.
The distance between the start and end points is the displacement. That "distance" is 180*sqrt(25) = 900 . The actual distance should be 180*4 + 180*3 = 720 + 540 = 1260. That's what a car's odometer or a bicycle odometer would read. the difference is 360.
I really do object to the wording, but what can I do?
Nine
Nine is the same thing as 8.
Displacement = sqrt(400^2 + 80^2)= sqrt(166400) = 408
The actual distance is 400 + 80 = 480
The difference is the answer = 480 - 408 = 72 <<<< Answer
Ten
This is just the displacement magnitude.
dis = sqrt(30^2 + 80^2)
dis = sqrt(900 + 6400)
dis = sqrt(7300)
dis = 85.44 <<<< Answer D
Twelve
Vi = 2.15*Sin(30) = 1.075 m/s
vf = 0
a = - 9.81
t = ?
<u>Formula</u>
a = (vf - vi)/t
<u>Solve</u>
-9.81 = (0 - 1.075)/t
- 9.81 * t = -1.075
t = 0.11 seconds
Thirteen
I'm leaving this last one to you. You need the initial height xo to answer it properly. Judging by the other questions, this one is right.
Edit
That is a surprise! Really quickly
d = 3.2 m
a = - 9.82
vf = 0
vi = ?
vf^2 = vi^2 - 2*a*d
0 = vi^2 - 2*9.81*3.2
vi = sqrt(19.62*3.2)
vi = 8.0 m/s But that is the vertical component of the speed
v = vi/sin(25)
v = 8.0/sin(25) = 11
Answer: f=150cm in water and f=60cm in air.
Explanation: Focal length is a measurement of how strong light is converged or diverged by a system. To find the variable, it can be used the formula:
= (nglass - ni)(
- 
).
nglass is the index of refraction of the glass;
ni is the index of refraction of the medium you want, water in this case;
R1 is the curvature through which light enters the lens;
R2 is the curvature of the surface which it exits the lens;
Substituting and calculating for water (nwater = 1.3):
= (1.5 - 1.3)(
- 
)
= 0.2(
)
f = 
= 150
For air (nair = 1):
= (1.5 - 1)( - )
f = 
= 60
In water, the focal length of the lens is f = 150cm.
In air, f = 60cm.
