Answer:
b) Expansion
Explanation:
In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.
Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.
A physical change can be defined as a type of change that involves an increase or decrease in the volume of a physical object (object). Also, this change can be reversed to the original state under certain conditions.
The increase in volume of matter that occurs when matter is heated causes an expansion.
This ultimately implies that, when a physical object (matter) is heated for a specific period of time, it result in an increase in the volume of the object; this phenomenon is generally referred to as expansion.
On the other hand, a decrease in volume of a physical object (matter) as a result of heat is known as contraction.
<h2>
Answer:</h2>
<em><u>Velocity of throwing arrow = 43.13 m/s.</u></em>
<h2>
Explanation:</h2>
In the question,
Let us say the height from which the arrow was shot = h
Distance traveled by the arrow in horizontal = 61 m
Angle made by the arrow with the ground = 2°
So,
From the <u>equations of the motion</u>,

Now,
Also,
Finally, the angle made is 2 degrees with the horizontal.
So,
Final horizontal velocity = v.cos20°
Final vertical velocity = v.sin20°
Now,
u = v.cos20° (No acceleration in horizontal)
Also,

So,
We can say that,

<em><u>Therefore, the velocity with which the arrow was shot by the archer is 43.13 m/s.</u></em>
Solve the equation.it is hard to see
Answer : The temperature of the hot reservoir (in Kelvins) is 1128.18 K
Explanation :
Efficiency of carnot heat engine : It is the ratio of work done by the system to the system to the amount of heat transferred to the system at the higher temperature.
Formula used for efficiency of the heat engine.

where,
= efficiency = 0.780
= Temperature of hot reservoir = ?
= Temperature of cold reservoir = 
Now put all the given values in the above expression, we get:



Therefore, the temperature of the hot reservoir (in Kelvins) is 1128.18 K