The electric current amount will vary according to the resistance value when connected to a voltage of a power supply. If resistance is reduced, current will increase. So, if the resistance is infinite (open circuit), the current could be considered zero, or infinitesimal small, if the resistance is zero (of infinitesimal small), the current will tend to be the maximum the power supply can provide. Here is the case of the power supply capability, input resistance, capacity to hold and regulate the output voltage to a certain maximum current, etc. Normally when you short circuit (zero ohms resi
Answer:
GIVEN
u is 40m/s and v=60m/s
time is 4s
therefore acceleration =60-40/4
=20/4=5m/s^2
b)next 2 sec=70m/s
Answer:
12 m/s
Explanation:
Using the continuity equation, which is an extension of the conservation of mass law
ρ₁A₁v₁ = ρ₂A₂v₂
where 1 and 2 indicate the conditions at two different points of flow, in this case, point 1 is any normal position in the pip and point 2 is the conditions at the restriction.
ρ = density of the fluid flowing; note that the density of the fluid flowing (water) is constant all through the fluid's flow
A₁ = Cross sectional Area of the pipe at point 1 = (πD₁²/4)
A₂ = Cross sectional Area of the pipe at the restriction = (πD₂²/4)
v₁ = velocity of the fluid flowing at point 1 = 3 m/s
v₂ = velocity of the fluid flowing at The restriction = ?
ρ₁A₁v₁ = ρ₂A₂v₂
Becomes
A₁v₁ = A₂v₂ (since ρ₁ = ρ₂)
(πD₁²/4) × 3 = (πD₂²/4) × v₂
3D₁² = D₂² × v₂
But
D₂ = (D₁/2)
And D₂² = (D₁²/4)
3D₁² = D₂² × v₂
3D₁² = (D₁²/4) × v₂
(D₁²/4) × v₂ = 3D₁²
v₂ = 4×3 = 12 m/s
Explanation:
a) P = IV
2000 W = I (230 V)
I = 8.7 A
b) The fuse must be rated for a higher current than the kettle, so use the 13A fuse.
c) Double insulation means there are two layers of insulation, insuring that the wires cannot touch the outer casing of the kettle and protecting the user from electrical shock.
d) V = IR
230 V = (8.7 A) R
R = 26.5 Ω
1) a) attract
The magnetic force between two magnetic poles is attractive for two unlike poles and repulsive for two like poles. Therefore we have:
1- For two north poles, the force between them is repulsive
2- For two south poles, the force between them is repulsive
3- For a north pole and a south pole, the force between them is attractive
In this problem, we are in the situation described in 3), so the force between the poles is attractive.
2) a) motion of electrons
While electric fields are produced by static electric charges, magnetic fields are produced by charges in motion (currents). In particular, a current in a wire (where a current is simply the motion of electrons inside the wire) produces a magnetic field whose intensity is
where
I is the current in the wire
r is the radial distance from the wire
And the direction of the field lines are such that the field form concentric circles around the wire.
