There is no "why", because that's not what happens. The truth is
exactly the opposite.
Whatever the weight of a solid object is in air, that weight will appear
to be LESS when the object is immersed in water.
The object is lifted by a force equal to the weight of the fluid it displaces.
It displaces the same amount of air or water, and any amount of water
weighs more than the same amount of air. So the force that lifts the
object in water is greater than the force that lifts it in air, and the object
appears to weigh less in the water.
Answer:
a. Wavelength = λ = 20 cm
b. Next distance of maximum intensity will be 40 cm
Explanation:
a. The distance between the two speakers is 20cm. SInce the intensity is maximum which refers that we have constructive interference and the phase difference must be an even multiple of π and equivalent path difference is nλ.
Now when distance increases upto 30 cm between the speakers, the sound intensity becomes zero which means that there is destructive interference and equivalent path is now increased from nλ to nλ + λ/2.
This we get the equation:
(nλ + λ/2) - nλ = 30-20
λ/2 = 10
λ = 20 cm
b. at what distance, sound intensity will be maximum again.
For next point calculation for maximum sound intensity, the path difference must be increased (n+1) λ. The distance must increase by λ/2 from the point of zero intensity.
= 30 + λ/2
= 30 + 20/2
=30+10
=40 cm
Answer:
The right answer is D) the total momentum of the system is 0.047 kg · m/s toward the right.
Explanation:
Hi there!
The total momentum of the system is given by the sum of the momentum vectors of each cart. The momentum is calculated as follows:
p = m · v
Where:
p = momentum.
m = mass.
v = velocity.
Then, the momentum of the system will be the momentum of cart A plus the momentum of cart B (let´s consider the right as the positive direction):
mA · vA + mB · Vb
0.450 kg · 0.850 m/s + 0.300 kg · (- 1.12 m/s) = 0.047 kg · m/s
The right answer is D) the total momentum of the system is 0.047 kg · m/s toward the right.
Answer:
Because the force is inversely proportional to the square of the distance
Explanation:
The magnitude of the electrostatic force between two charged particles is given by
where
k is the Coulomb's constant
q1, q2 are the magnitudes of the two charges
d is the distance between the two charges
We observe that the magnitude of the force is inversely proportional to the square of the distance.
Therefore, when the distance changes to
The force will double:
Answer:
a) Fi = 85.76 N
b) Fi = 87.8 N
Explanation:
Given:-
- Density of hydraulic oil, ρ = 804 kg/m^3
- The radius of input piston, ri = 0.00861 m
- The radius of output piston, ro = 0.141 m
Find:-
What input force F is needed to support the 23000-N combined weight of a car and the output plunger, when
(a) the bottom surfaces of the piston and plunger are at the same level
(b) the bottom surface of the output plunger is 1.10 m above that of the input plunger?
Solution:-
For part a.
- We see that both plungers are equal levels or there is no pressure due to elevation head. So we are only dealing with static pressure exerted by the hydraulic oil on both plungers to be equal. This part is an application of Pascal's Law:
Pi = Po
Fi / Ai = Fo / Ao
Fi = Ai / Ao * Fo
Fi = (ri/ro)^2 * Fo
Fi = ( 0.00861 / 0.141 )^2 * 23000
Fi = 85.76 N
For part b.
- We see that both plungers are at different levels so there is pressure due to elevation head. So we are only dealing with static pressure exerted by the hydraulic oil on both plungers plus the differential in heads. This part is an application of Bernoulli's Equation:
Pi = Po + ρ*g*h
Where, h = Elevation head = 1.10m
Fi = (ri/ro)^2 * Fo + ρ*g*h*π*ri^2
Fi = 85.76 + (804*9.81*1.1*3.142*0.00861^2)
Fi = 87.8 N
