Answer:
t=1.4hours
Explanation:
The half life is 1hour
At t=0 he has a mass of 4kg
So he want it to be 1kg, so that his weapon can work.
Applying the exponential function of decay
M=Cexp(-kt)
Where,
M is the mass at any time
C is a constant of integration
k is the rate of decay
Given that it has an half life of 1 hours.
Then k is 1
At t =0 the mass is 4kg
Therefore
4=Cexp(0)
C=4
M=4exp(-kt)
Since rate of decay is 1, then k=1
M=4exp(-t)
We need to find t at M=1kg
1=4exp(-t)
1=4exp(-t)
1/4=exp(-t)
0.25=exp(-t)
Take In of both sides
In(0.25)=-t
-1.3863=-t
Then, t=1.386hour
Then it will take about 1.4 hours to get to 1kg.
Interesting question. I'd take a guess that it could be either mirrors and light travelling in straight lines and being reflected, or optical fibres to achieve a perhaps similar result.
Answer:
Part a)

Part b)

Explanation:
As we know that the energy of capacitor when it is not connected to potential source is given as

As we know that initial energy is given as

now we know that capacitance of parallel plate capacitor is given as

now the new capacitance when distance is changed from 3.80 mm to 1.45 mm



Now the new energy of the capacitor is given as


Part b)
Now if the voltage difference between the plates of capacitor is given constant
now the energy energy of capacitor is


now when capacitance is changed to new value then new energy is given as



Answer:
a jak to chces vidieť nápis podrobnejsie
F=nmv
where;
n=no. of bullets = 1
m=mass of bullets=2g *10^-3
V=velocity of bullets200m/sec
F=1
loss in Kinetic energy=gain in heat energy
1/2MV^2=MS∆t
let M council M
=1/2V^2=S∆t
M=2g
K.E=MV^2/2
=(2*10^-3)(200)^2/2
2 councils 2
2*10^-3*4*10/2
K.E=40Js
H=mv∆t
(40/4.2)
40Js=40/4.2=mc∆t
40/4.2=2*0.03*∆t
=158.73°C