Answer:
Einstein's general theory of relativity is the theory behind black holes has been tested with a wide range of experiments of which all confirm the predictions the theory makes. We cannot see black holes phenomena inside the event horizon, we do observe things outside this limit.
Black holes in binary star systems leave signs of their presence on neighboring star thats detected and the signs include X-ray emissions, accretion disks, and large orbit perturbations.
this is the evidence that astronomers and physicists have to show that the theory about black holes is correct.
Answer:


Explanation:
<u><em>Finding the net force:</em></u>
<u><em>Firstly , we'll find force of Friction:</em></u>

Where
is the coefficient of friction and m = 13.6 kg


<u><em>Now, Finding the net force:</em></u>


<u><em>Finding Acceleration:</em></u>



Answer:
Explanation:
Velocity by definition means speed and direction of an object. This means it has a value and a positive or minus sign indicating direction. Speed is the absolute value of velocity because there is no direction correlated with speed. If you add a direction, it is then called velocity
D.) In order to calculate both of them, we must know the "FORCE" on the system.
M = mass of aluminium = 1.11 kg
= specific heat of aluminium = 900
= initial temperature of aluminium = 78.3 c
m = mass of water = 0.210 kg
= specific heat of water = 4186
= initial temperature of water = 15 c
T = final equilibrium temperature = ?
using conservation of heat
Heat lost by aluminium = heat gained by water
M
(
- T) = m
(T -
)
(1.11) (900) (78.3 - T) = (0.210) (4186) (T - 15)
T = 48.7 c