Answer:
d. the atomic number remains the same.
Explanation:
First at all it's important to know how to read nuclear information

X is the atomic symbol, A the mass number and Z the atomic number of the element.
Gamma rays emitted on gamma decay are characterized as 
If we write the nuclear equation for the decay, we have that:

The sum of the mass numbers and atomic numbers on the right side has to be equal to the left side numbers of the equation, that means the mass number and the atomic number remains the same for the resulting atom to preserve the equality.
C, They change their shapes depending on their containers
Answer:
=6.5%
Explanation:
Mass of the ball:
]
Initial velocity of the ball: 
final velocity of the ball:
which is -30/100 of
=
Mass of the bottle: 
Initial velocity of the bottle: 
final velocity of the bottle:
is unknown (to find)
<em>by using conservation momentum, which stated that the initial momentum is equal to the final momentum.</em>
<em />
<em />
<em>so since the bottle is at rest firstly, therefore </em>
<em />
<em />
<em />
<em />
<em> </em><em>equation 1</em>
so now substitute
into equation 1

<em />
<em />
<em>collect the like terms</em>


divide both side by 

Now substitute

6.5%
<em />
Answer:
93 km/h
Explanation:
Given that a bus took 8 hours to travel 639 km. For the first 5 hours, it travelled at an average speed of 72 km/h
Let the first 5 hours journey distance = F
From the formula of speed,
Speed = distance/time
Substitute speed and time
72 = F/5
F = 72 × 5 = 360 km
The remaining distance will be:
639 - 360 = 279km
The remaining time will be:
8 - 5 = 3 hours
Speed = 279/3
Speed = 93 km/h
Therefore, the average speed for the remaining time of the journey is equal to 93 km/h