Answer:
= 230.8 ohms
Explanation:
From ohms law, V = IR
R=V/I
R = 120 ÷ 0.520
R = 230.8 ohms
convection
radiation
all of the above
Answer:
radiation is the answer
Answer: a) B = 6811N
b) m = 603.2kg
c) 86.8%
Explanation: Buoyant force is a force a fluid exerts on a submerged object.
It can be calculated as:
where:
is density of the fluid the object is in;
is volume of the object;
g is acceleration due to gravity, is constant and equals 9.8m/s²
a) For the hollow plastic sphere, density of water is 1000kg/m³:
B = 6811N
b) Anchored to the bottom, the forces acting on the sphere are Buoyant, Tension and Force due to gravity:
B = T +
B = T + mg
mg = B - T
Calculating:
m = 603.2kg
c) When the shpere comes to rest on the surface of the water, there are only buoyantandgravity acting on it:
B = m.g
= 0.6032m³
Fraction of the submerged volume is:
= = 0.868
We use the principles of buoyancy and Archimedes' principle to calculate the buoyant force, the mass of the sphere, and the fraction of volume submerged when the cord breaks. The buoyant force equals the weight of water displaced by the sphere, we will find this by calculating the difference between the weight of the sphere in air and its weight when submerged in water. The sphere's mass can be found using its volume and the density of plastic, whilst the fraction of volume volume submerged when the cord breaks will be such that the weight of water displaced equals the weight of the sphere.
To answer these questions, we will apply the principles of buoyancy and Archimedes' principle. Archimedes' principle states that the buoyant force on an object is equal to the weight of fluid displaced by the object. Buoyant force is hence the difference between the weight of the object in air and its weight when submerged in water.
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An ideal ammeter has zero resistance to avoid altering the current it measures, while an ideal voltmeter has infinite resistance to prevent drawing current from the device it's measuring the voltage of.
The resistance of an ideal ammeter is zero ohms. This ensures that it doesn't interfere with the current it is measuring. An ammeter is connected in series with the circuit, and if the resistance were greater than zero, it would decrease the amount of current circulating in the circuit.
On the other hand, an ideal voltmeter has infinite resistance. This happens because a voltmeter is connected in parallel with a device to measure its voltage, and to avoid drawing current from the device, an ideal voltmeter should have infinite resistance.
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b. commutator.
c. brush spring.
d. relay.