1) 333.6 C
In order to have breakdown, the electric field at the surface of the cloud must be equal to the breakdown electric field:

The electric field strength at the surface of a charged sphere is given by

where
is the vacuum permittivity
Q is the charge on the sphere
R is the radius of the sphere
Here we have a cloud of radius

So we can re-arrange the previous equation in order to find the charge on the cloud:

2)
excess electrons
The total charge of the cloud must be (in magnitude)
Q = 333.3 C
We know that one electron carries a charge of

The total charge is just given by the charge of each electron multiplied by the number of excess electrons in the cloud:

where
N is the number of excess electrons
Solving for N, we find:

Answer: Fr = 26.53 N
Explanation: The constant force exerted on the block by the surface is the frictional force.
This frictional force is as a result of interaction between the body and the surface.
According to newton's second law of motion,
F - Fr = ma
F=applied force
Fr = magnitude of frictional force
m = mass of object = 12kg
a = acceleration of object = 3.2m/s²
The applied force (F= 75 N) is inclined at an angle of 30° to the horizontal thus making it have 2 components of forces given below
Fx = 75 * cos 30 = 64.95 N (horizontal component)
Fy = 75 * sin 30 = 37.5 N ( vertical motion)
The body moves across the surface, hence the horizontal component of force is responsible for motion.
F = 64.95 N
By substituting the parameters, we have that
64.96 - Fr = 12 * 3.2
64.96 - Fr = 38.4
Fr = 64.96 - 38.4
Fr = 26.53 N
Answer:
1800J
Explanation:
Step one:
given data
mass of bullet m= 3g= 0.03kg
initial velocity u = 400m/s
final velocity v= 200 m/s
Step two:
1.The bullet's lost kinetic energy went inside the tree.
2. The energy transferred is computed as
= initial KE- KE final
Initial KE= 1/2mu^2
Initial KE= 1/2*0.03*400^2
Initial KE= 1/2*0.03*160000
Initial KE= 1/2*4800
Initial KE= 2400J
KE final= 1/2mv^2
KE final= 1/2*0.03*200^2
KE final= 1/2*0.03*40000
KE final= 1/2*1200
KE final= 600J
KE transferred = 2400-600
KE transferred= 1800J
If 56.5kJ are needed to raise the temp by 90°C and if the heater is 60% efficient that means that:
60% X y = 56.5kJ
where y is the electrical energy in kJ that the heater will use.
y = 94.2kJ
Answer:
The horizontal displacement is 
Explanation:
From the question we are told that
The angle at which the string is maintained is 
The length of string reeled in is 
Using the SOHCAHTOA formula
We have that the hypotenuse(Hyp) is l = 152
Hence the horizontal displacement of the kite which is the Adjacent(Adj) can be evaluated as

substituting values

=> 