Explanation:
Initial time, t₁ = 2:30 pm
Final time, t₂ = 2:30:45
We need to find the motion of students in terms of time. Final time is 45 seconds more than the initial time.
Change in time,

Hence, this is the required solution.
Answer:
The distance between the earth and the star is increasing.
Explanation:
When we observe an object and its electromagnetic radiation has been displaced to blue, it means that it is getting closer to us, causing the light waves it emits to get closer together and its wavelength to decrease towards blue, this is knowm as blueshift.
On the contrary, when an object is rapidly moving away from us, the light waves or electromagnetic radiation it emits have been stretched from their normal wavelength to a longer wavelength, towards the red part of the spectrum. This is known as redshift.
This phenomenon of changes in wavelength and frequency due to movement (whether the source approaches or moves away) is described by the Doppler effect.
So for this case because the light we perceive from the star has moved to the red part of the visible spectrum, we can conclude that it is moving away from the earth, and that the distance between the star and the earth is increasing.
(D) The gravitational force between the astronaut and the asteroid.
Reason :
All the other forces given in the options, except (D), doesn't account for the motion of the astronaut. They are the forces that act between nucleons or atoms and neither of them accounts for an objects motion.
Answer:
The final temperature of the object will be 42.785 °C
Explanation:
When the heat added or removed from a substance causes a change in temperature in it, this heat is called sensible heat.
In other words, sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change), so that the temperature varies.
The equation for calculating the heat exchanges in this case is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.
In this case:
- Q= 450 J
- c= 2.89

- m= 20 g
- ΔT= Tfinal - Tinitial= Tfinal - 35 °C
Replacing:
450 J= 2.89
*20 g* (Tfinal - 35°C)
Solving for Tfinal:

7.785 °C=Tfinal - 35°C
7.785 °C + 35°C= Tfinal
42.785 °C=Tfinal
<u><em>The final temperature of the object will be 42.785 °C</em></u>