F=nmv
where;
n=no. of bullets = 1
m=mass of bullets=2g *10^-3
V=velocity of bullets200m/sec
F=1
loss in Kinetic energy=gain in heat energy
1/2MV^2=MS∆t
let M council M
=1/2V^2=S∆t
M=2g
K.E=MV^2/2
=(2*10^-3)(200)^2/2
2 councils 2
2*10^-3*4*10/2
K.E=40Js
H=mv∆t
(40/4.2)
40Js=40/4.2=mc∆t
40/4.2=2*0.03*∆t
=158.73°C
Answer:
Option C
100 J
Explanation:
Kinetic energy, KE is given by
where m is the mass and v is the velocity
Substituting 50 Kg for mass, m and 2 m/s for velocity v then we obtain
Therefore, the child's kinetic energy is equivalent to 100 J
Answer:
B) the sound source moves towards you at 100 m/sec
Explanation:
The Dopper Effect is a phenomenon that occur when there is relative motion between an observer and a source of a wave. When this situation occurs, there is an apparent shift in frequency of the wave, as observed by the observer.
The apparent frequency observed by the observer is given by
where
f is the original frequency of the wave
f' is the apparent frequency
v is the speed of the wave
is the velocity of the observer (positive if moving towards the source of the wave, negative otherwise)
is the velocity of the source (negative if moving towards from the observer, positive otherwise)
In this problem, we want to find the scenario in which the sound frequency is higher.
We see that in all 4 scenarios, the sound source is moving: this means we have to find the scenario in which the denominator of the equation is smaller.
First of all, we notice the sound source moves towards the observer, is negative, so the denominator is higher: this means that the correct option must be either A or B.
Also, we notice that since is negative, a value larger in magnitude will mean a smaller denominator: therefore, the correct answer will be
B) the sound source moves towards you at 100 m/sec
Since this situation will make the denominator of the formula the smallest possible.
Taking into account the definition of molarity, the concentration of a solution that contains 70 g of H₂SO₄ in 0,28 dm³ of solution is 2.5510 .
Molar concentration or molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution:
Molarity is expressed in units .
In this case, you have:
Replacing in the definition of molarity:
Solving:
<u><em>Molarity= 2.5510 </em></u>
Finally, the concentration of a solution that contains 70 g of H₂SO₄ in 0,28 dm³ of solution is 2.5510 .
Learn more about molarity:
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