Answer: a)
Explanation:
The buoyant force, as stated by Archimedes’ principle, is equal to the weight of the liquid that occupies the same volumen as the submerged object, as follows:
Fb = δ.V.g
If this force is larger than the weight of the object (that means that the fluid is denser than the solid), the object floats, which is the case for silver and mercury.
Instead, silver density is larger than water density, which explains why the pure silver ingot sinks.
Finally, as mercury is denser than water, we conclude that for a same object, the buoyant force in mercury is larger than in water (exactly 13.6 times greater).
Answer:
The frequency is 
Explanation:
From the question we are told that
The time taken for it to decay to half its original size is 
Let the voltage of the capacitor when it is fully charged be 
Then the voltage of the capacitor at time t is said to be 
Now this voltage can be mathematical represented as
Where RC is the time constant
substituting values
Generally the cross-over frequency for a low pass filter is mathematically represented as
substituting values
Answer:
B
Explanation:
The capacitor is a component which has the ability to store energy in the form of an electrical charge making a potential difference on those two metal plates
A capacitor consists of two or more parallel conductive (metal) plates. They are electrically seperated by an insulating material (ex: air, mica,ceramic etc.) which is called as Dielectric Layer
Due to this insulating layer, DC current can not flow through the capacitor.But it allows a voltage to be present across the plates in the form of an electrical charge.
Answer:
It took the projectile 120 s to reach the maximum height.
Explanation:
Given;
maximum height of the projectile, s = 180 km = 180,000 m
initial speed of the projectile, u = 3 km/s = 3000 m/s
final velocity at maximum height, v = 0
Apply the following kinematic equation for average velocity of the projectile;
Therefore, it took the projectile 120 s to reach the maximum height.
Answer:
a) I = 13.04 A
b) R = 8.82 ohms
c) 1291.87 kilocalories are generated an hour.
Explanation:
let P be the power of the heater, V be the voltage of the heater, I be the current of the heater, R be the resistance.
a) we know that:
P = I×V
I = P/V
= (1500)/(115)
= 13.04 A
Therefore, the current of the heater is 13.04 A
b) we now have voltage and current, according to Ohm's law:
R = V/I
= (115)/(13.04)
= 8.82 ohms
Therefore, the resistance of the heating coil is 8.82 ohms.
c) the number of kilocalories generated in one hour by the heater is just the energy the heater produces in one hour which is given by:
E = P×t
= (1500)(1×60×60)
= 5400000 J
since 1 calorie = 4.81 J
1 kilocalorie = 0.001 calories
E = 5400000/4.18 ≈ 1291866.029 calories ≈1291.87 kilocalories
Therefore, 1291.87 kilocalories are produced/generated in one hour.
