Answer:
The initial velocity is 50 m/s.
(C) is correct option.
Explanation:
Given that,
Time = 10 sec
For first half,
We need to calculate the height
Using equation of motion

....(I)
For second half,
We need to calculate the time
Using equation of motion



Put the value of h from equation (I)


According to question,


Put the value of t₁ and t₂



Here, g = 10 
The initial velocity is


Hence, The initial velocity is 50 m/s.
 
        
             
        
        
        
For rotational equilibrium of the door we can say that torque due to weight of the door must be counter balanced by the torque of external force

here weight will act at mid point of door so its distance is half of the total distance where force is applied
here we know that

now we will have


so our applied force is 72.5 N
 
        
             
        
        
        
The equation of D = m/V
Where D = density
m = mass
and V = volume
We are solving for V, so with the manipulation of variables we multiply V on both sides giving us 
V(D) = m 
now we divide D on both sides giving us
V = m/D 
We know our mass which is 600g and our density is 3.00 g/cm^3
so
V = 600g/3.00g/cm^3 = 200cm^3  or 200mL
a cubic centimeter (cm^3) is one of the units for volume. It's exactly like mL. 1 cm^3 = 1 mL
 
If you wish to change it to L, you'd have to convert. 
        
             
        
        
        
Power= current*voltage or P=IV
so 16 watts=I*7 volts
divide on both sides to isolate I so you get 
I= 16/7 which is about 2.3 amps
 
        
             
        
        
        
Answer:
5.096*10^-8
Explanation:
Given that
The average value of the electromagnetic wave is 310 mW/m²
To find the maximum value of the magnetic field the wave is closest to, we say
Emax = √Erms
Emax = √[(2 * 0.310 * 3*10^8 * 4π*10^-7)]
Emax = √233.7648
Emax = 15.289
Now, with our value of maximum electromagnetic wave gotten, we divide it by speed of light to get our final answer
15.289 / (3*10^8) = 5.096*10^-8 T
Suffice to say, The maximum value of the magnetic field in the wave is closest to 5.096*10^-8