Answer:
Distance = 16.9 m
Explanation:
We are given;
Power; P = 70 W
Intensity; I = 0.0195 W/m²
Now, for a spherical sound wave, the intensity in the radial direction is expressed as a function of distance r from the center of the sphere and is given by the expression;
I = Power/Unit area = P/(4πr²)
where;
P is the sound power
r is the distance.
Thus;
Making r the subject, we have;
r² = P/4πI
r = √(P/4πI)
r = √(70/(4π*0.0195))
r = √285.6627
r = 16.9 m
Answer:
Explanation:
Frictional force acting on the child = μ mg cosθ
, μ is coefficient of kinetic friction , m is mass of child θ is inclination
work done by frictional force
μ mg cosθ x d , d is displacement on inclined plane
work done = .13 x 276 x cos34 x 5.9
= 175.5 J
This work will be converted into heat energy.
b ) Initial energy of child = mgh + 1/2 m v ² , h is height , v is initial velocity
= 276 x 5.9 sin34 + 1/2 x 276 / 9.8 x .518² [ mass m = 276 / g ]
= 910.59 + 3.77
= 914.36 J
loss of energy due to friction = 175.5
Net energy at the bottom
= 738.86 J
If v be the velocity at the bottom
1/2 m v² = 738 .86
.5 x (276 / 9.8) x v² = 738.86
v² = 52.47
v = 7.24 m /s .
Answer:
<h2>Potential difference across capacitors in parallel
</h2>
Two or more capacitors are said to be connected in parallel if each one of them is connected across the same two points. In a parallel combination of capacitors potential difference across each capacitor is same but each capacitor will store different charge.
Answer:
C)Before leaving for their trip, turn the central heating system off, along with lights and electrical household appliances.
Explanation:
Although, the other three options will also reduce their electricity bill but they do not explain why Mr. Hernandez's family got same electricity bill as last year even though this time they were not home for one and a half week. Also, A), B) and D) ideas are not reasonable.
So, the only conclusion is that even when they were on a vacation. the electrical appliances in their home were on. That's why the bill remained the same.
The idea of turning the central heating system off, along with lights and electrical household appliances before they leave for the trip will help reduce the energy usage. Also, it is reasonable.
The momentum of block B afterwards is 
.
Explanation:
We can solve this problem by applying the principle of conservation of momentum.
In fact, the total momentum before and after the collision must be conserved. Therefore, we can write:
where:
is the initial momentum of block A
is the initial momentum of block B
is the final momentum of block A
is the final momentum of block B
Solving for , we find:
So, the momentum of block B afterwards is .
Learn more about momentum:
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