Answer : The correct option is, (d) 
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
= specific heat of copper = 
= specific heat of water = 
= mass of copper = 120 g
= mass of water = 300 g
= final temperature of mixture = 
= initial temperature of copper = ?
= initial temperature of water =
Now put all the given values in the above formula, we get:


Therefore, the temperature of the kiln was, 
(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.
First, before determining which variable is which, we go over the definition of each.
The independent variable is the one which is intentionally changed in order to investigate its effect on the dependent variable.
The dependent variable is monitored and changes occur in it due to the changing conditions of the independent variable.
In this case, the location of the African violets is the independent variable as it is intentionally changed, while the rate of growth of the African violets is the dependent variable as it is being measured.
Fnety = (FT)(sin 32°) – Fg
Or the answer B, I checked it.
Answer:
1.1 sec
Explanation:
m = mass of the box = 8 kg
k = spring constant of the spring = 69 N/m
v = initial speed of the box = 1.5 m/s
t = time period of oscillation of box in contact with the spring
Time period is given as

Inserting the values

t = 1.1 sec