Answer:
E/4
Explanation:
The formula for electric field of a very large (essentially infinitely large) plane of charge is given by:
E = σ/(2ε₀)
Where;
E is the electric field
σ is the surface charge density
ε₀ is the electric constant.
Formula to calculate σ is;
σ = Q/A
Where;
Q is the total charge of the sheet
A is the sheet's area.
We are told the elastic sheet is a square with a side length as d, thus ;
A = d²
So;
σ = Q/d²
Putting Q/d² for σ in the electric field equation to obtain;
E = Q/(2ε₀d²)
Now, we can see that E is inversely proportional to the square of d i.e.
E ∝ 1/d²
The electric field at P has some magnitude E. We now double the side length of the sheet to 2L while keeping the same amount of charge Q distributed over the sheet.
From the relationship of E with d, the magnitude of electric field at P will now have a quarter of its original magnitude which is;
E_new = E/4
In Burglar alarm, LDR acts an AND gate.
Answer: C
Explanation
The LDR is light dependent resistor. The principle used in the working of LDR is that the resistance is inversely proportional to the intensity of light falling on the diode.
In burglar alarm, LDR diode is combined with an IC 555.
Normally an LED source is made to be incident on the LDR diode with same intensity such that the resistance will be maintained constant.
As the LDR is connected with IC, the voltage will be high when light is falling on the diode.
The IC will give only two output states that is high and low. This confirms that LDR in burglar alarm act as AND gate.
As the thief enters and crosses the LED light, the intensity of the light falling on the diode will decrease leading to decrease in the voltage which will cause the alarm to beep.
<span>(a)
Taking the angle of the pitch, 37.5°, and the particle's initial velocity, 18.0 ms^-1, we get:
18.0*cos37.5 = v_x = 14.28 ms^-1, the projectile's horizontal component.
(b)
To much the same end do we derive the vertical component:
18.0*sin37.5 = v_y = 10.96 ms^-1
Which we then divide by acceleration, a_y, to derive the time till maximal displacement,
10.96/9.8 = 1.12 s
Finally, doubling this value should yield the particle's total time with r_y > 0
<span>2.24 s
I hope my answer has come to your help. Thank you for posting your question here in Brainly.
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The solution for this problem is:
r = [(2.90 + 0.0900t²) i - 0.0150t³ j] m/s²
this is for t in seconds and r in meters
v = dr/dt = [0.180t i - 0.0450t² j] m/s²
tan(-36.0º) = -0.0450t² / 0.180t
0.7265 = 0.25t
t = 2.91 s is the velocity vector of the insect
Answer:
B) Kinetic energy increases, potential energy decreases
Explanation:
In a given system, when a body is at rest, v =0m/s, the kinetic energy is at zero while the potential energy is at maximum. However, when a body is in motion with a velocity = v, the potential energy is at zero while the kinetic energy is at maximum.
Before this happen, the a body at rest (P.E = max) is set on motion, the kinetic energy gradually increases till it converts all the potential energy in the system to kinetic energy and then reverses back when the body goes to rest again.
In this case, before the batter hits the ball, the kinetic energy was at zero while the potential energy was at maximum. However, when he hits the ball and sets it into motion with a velocity V, the potential energy converts to kinetic energy and moves the ball with that energy till it has expanded it and comes to rest.
Potential Energy → Kinetic Energy → Potential Energy.
That's how the system keeps changing.
