Răspuns:
7: 4
Explicaţie:
Formula pentru calcularea cantității de căldură absorbită este exprimată ca;
Q = mc∆t
m este masa substanței
c este capacitatea termică specifică
∆t este schimbarea temperaturii
Conform legii calorimetriei, căldura pierdută de substanța rece = căldura câștigată de substanța fierbinte.
Folosind formula
(mc∆t) rece = (mc∆t) fierbinte
McCw∆tc = MhCw∆th
Deoarece au aceeași capacitate de căldură specifică, se vor anula. Ecuația devine;
Mc∆tc = Mh∆th ...... 1
Pentru apa rece;
∆tc = 45 ° C - 10 ° C
∆tc = 35 ° C
Pentru apa fierbinte:
∆th = 65 ° C - 45 ° C
∆th = 20 ° C
Înlocuiți în ecuația 1;
Mc (35) = Mh (20)
35Mc = 20Mh
Luând raportul dintre masa apei reci și cea fierbinte:
Mh / Mc = 35/20
Mh / Mc = 7/4
Prin urmare, lichidul trebuie amestecat împreună în raportul 7: 4
Answer:
The book remained in its state of rest before the car started to move forward as no direct force acted on it.
Explanation:
According to Newton's first law of motion, a body will continue in its present state of rest, or if it is in motion, will continue to move with uniform speed in a straight line unless aced upon by an external force. This tendency of a body to remain in its state of reset or uniform motion in a straight line is known as inertia and is directly proportional to the mass of the body. The more massive a body, the more inertia it possesses. Thus Newton's first law is also known as the law of inertia.
Considering the case of the book on the dashboard of a stationary car which suddenly starts to move. While the car is stopped at the traffic light, the dashboard where the book sits and the book are both at rest. When the car begins to move forward, the dashboard moves forward with it. However as the book is not a part of the car, no force is directly acting on it, so the book so it stays at rest due to its inertia.
Therefore, as the car is moving forward, the stationary book appears to move backward from the reference point of the car, sliding off the dashboard.
Answer:
Tension in the string will increase
Explanation:
As we know that tension in the string at any angle with the vertical is given as
now we have
also we know that
angular speed of the stone is directly depending on the time period of the motion
so it is given as
since the frequency of the revolution is increased from n = 1 rev/s to 2 rev/s
so the angular speed would be doubled
So here we can say that
tension in the string will increase when we will increase the frequency of revolution.
