Answer:
No work is performed or required in moving the positive charge from point A to point B.
Explanation:
Lets take
Q= Positive charge which move from  point A to point B along 
Voltage difference,ΔV =V₁ - V₂  
The work done 
W = Q . ΔV
Given that  charge is moved from point A to point B along an equipotential surface.It means that voltage  difference is zero.
ΔV = 0
So
W = Q . ΔV
W = Q x 0
W= 0 J
So work is zero.
 
        
             
        
        
        
Answer:
The distance between the camera and the rock is 836.6 cm
Explanation:
A right triangle is formed where the hypotenuse (h) is the distance between the rock and the camera. One of the leg (l) is the distance between the camera and the surface. The angle between the hypotenuse and this leg is α = 90° - 13.69° = 76.31°. By definition:
cos α = adjacent/hypotenuse
cos(76.31) = 198.0/h
h = 198.0/cos(76.31) 
h = 836.6 cm
 
        
             
        
        
        
The power equals energy divided by the time
P=E/t
P=1200/60
P=20W
Hope you get it!
 
        
             
        
        
        
Answer:
The fundamental wavelength of the vibrating string is 1.7 m.
Explanation:
We have,
Velocity of wave on a guitar string is 344 m/s
Length of the guitar string is 85 cm or 0.85 m
It is required to find the fundamental wavelength of the vibrating string. The fundamental frequency on the string is given by :

Now fundamental wavelength is :

So, the fundamental wavelength of the vibrating string is 1.7 m.
 
        
             
        
        
        
Answer:
v = 21.25 km/h
The average velocity is 21.25km/h
Explanation:
Average velocity = total displacement/time taken
v = d/t
Given;
A car travels 50 km in 25 km /h
d1 = 50km
v1 = 25km/h
time taken = distance/velocity
t1 = d1/v1
t1 = 50/25 = 2 hours
 and then travels 60km with a velocity 20 km/h
d2 = 60km
v2 = 20km/h
t2 = d2/v2 = 60/20
t2 = 3 hours
 and then travels 60km with a velocity 20 km/h in the same direction
d3 = 60km
v3 = 20km/h
t3 = d3/v3 = 60/20
t3 = 3 hours
Average velocity = total displacement/total time taken
 v = (d1+d2+d3)/(t1+t2+t3)
v = (50+60+60)/(2+3+3)
v = 170/8
v = 21.25 km/h
The average velocity is 21.25km/h