Answer:
The kinetic energy K of the moving charge is K = 2kQ²/3d = 2Q²/(4πε)3d = Q²/6πεd
Explanation:
The potential energy due to two charges q₁ and q₂ at a distance d from each other is given by U = kq₁q₂/r.
Now, for the two charges q₁ = q₂ = Q separated by a distance d, the initial potential energy is U₁ = kQ²/d. The initial kinetic energy of the system K₁ = 0 since there is no motion of the charges initially. When the moving charge is at a distance of r = 3d, the potential energy of the system is U₂ = kQ²/3d and the kinetic energy is K₂.
From the law of conservation of energy, U₁ + K₁ = U₂ + K₂
So, kQ²/d + 0 = kQ²/3d + K
K₂ = kQ²/d - kQ²/3d = 2kQ²/3d
So, the kinetic energy K₂ of the moving charge is K₂ = 2kQ²/3d = 2Q²/(4πε)3d = Q²/6πεd
Answer:
Tangential acceleration is in the direction of velocity - along the circumference of a circle if the object is undergoing circular motion
a = (V2 - V1) / T
Radial acceleration is perpendicular to the direction of motion if the object is not moving in a straight line (perhaps along the circumference of a circle)
a = m V^2 / R = m ω^2 R where R is the radius vector of the velocity - note that the Radius vector is directed from the center of motion to the object and for circular motion would be constant in magnitude but not in direction
The cost of boiling 500cm3 of water using the 3kW kettle is 1.35 P.
<h3>
Cost of electricity for 3 kW kettle</h3>
The cost is calculated as follows;
1 unit = 9p /kWh
Total energy consumed by 3 kW kettle, E = P x t
where;
- P is power (kW)
- t is time in (hr)
E = 3 kW x (3 mins/60 mins/hr)
E = 0.15 kWh
Energy cost = 9 p/kWh x 0.15 kWh = 1.35 P
Thus, the cost of boiling 500cm3 of water using the 3kW kettle is 1.35 P.
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When the magnets are released and begin to move, the magnetic force changes potential energy into kinetic energy;<u> option D</u>
<h3>What is magnetic force?</h3>
Magnetic force can be defined as the force of attraction or repulsion that is felt or produced between the magnetic poles and electrically charged moving particles.
Magnetic force is the force that exists due to the attractio or repulsion of objects place around the region of space where a maget exerts its force.
When a magnet is released ai a system of magnets and allowed to move it increases the kinetic eergy of the system by converting potential energy to kinetic energy.
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Answer:
77%
Explanation:
efficiency= work output/work input X 100%
e = 1,200j/ 1,550 j x100%
e = 1,200/1,550= 0.77
e = 0.77 x 100%
e = 77%