Answer:
The new distance is d = 0.447 d₀
Explanation:
The electric out is given by Coulomb's Law
F = k q₁ q₂ / r²
This electric force is in balance with tension.
We reduce the charge of sphere B to 1/5 of its initial value (=q₂ = q₂ / 5) than new distance (d = n d₀)
dat
q₁ =
q₂ =
r = d₀
In order for the deviation to maintain the electric force it should not change, so we apply the Coulomb equation for the two points
F = k q₁ q₂ / d₀²
F = k q₁ (q₂ / 5) / (n d₀)²
.k q₁ q₂ / d₀² = q₁ q₂ / (5 n² d₀²)
5 n² = 1
n = √ 1/5
n = 0.447
The new distance is
d = 0.447 d₀
Answer
Mass m = 78 kg
Vertical height in each stage h = 11 m
(a).
Initial speed u = 0
Final speed v = 1.1 m / s
a = 0.055 m/s²
Work done
(b).Work done
W_b = 78× 9.8× 11
c)
Work done
Where V = final speed
= 0
v = 1.1 m / s
for deceleration a = -0.055 m/s²
now,
W_c = 545.75 × 11
Answer:
100 J, 225 J
Explanation:
The kinetic energy of an object is given by:
where
m is the mass of the object
v is the velocity of the object
In this problem, the initial kinetic energy of the object is
K = 25 J
Then, the velocity is doubled, which means
v' = 2v
Therefore, the new kinetic energy will be
Therefore, the kinetic energy has quadrupled:
Later, the velocity is tripled, which means
v'' = 3v
Therefore, the new kinetic energy will be
Therefore, the kinetic energy has increased by a factor of 9:
1. The magnitude of the magnetic field doubles
Explanation: the intensity of the magnetic field produced by a current-carrying wire is given by:
where is the vacuum permeability, I is the current in the wire, r is the distance from the wire.
As we see from the formula, the intensity of the magnetic field is directly proportional to the current: if the current increases from 5 A to 10 A, it means it doubles, so the magnetic field doubles as well.
2. The magnitude of the magnetic field halves
Explanation: the intensity of the magnetic field produced by a current-carrying wire is given by:
We see that the magnitude of the magnetic field is inversely proportional to the distance from the wire (r). In this case, the distance of the particle is changed from 10 cm to 20 cm, so it is doubled: therefore, the magnitude of the field will become half of the initial value.
3. The force reverses direction
Explanation: the force exerted on a charged particle in a magnetic field is:
where q is the charge, v is the speed of the particle, B is the magnetic field intensity and the angle between the direction of v and B. If the charge of the particle is switched from 2 µC to –2µC, the magnitude of the force does not change (because the absolute value of q does not change), however the charge q gets a negative sign (-), so the sign of the force changes and gets a negative sign too, so the force reverses direction.