Hello!
The balloon explodes, because the pressure builds up inside and the air want to expand. Letter a)
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Answer:
a)  &
       &        
b) 
c) 
Explanation:
Given:
mass of the book, 
combined mass of the student and the skateboard, 
initial velocity of the book, 
angle of projection of the book from the horizontal, 
a) 
velocity of the student before throwing the book:
Since the student is initially at rest and no net force acts on the student so it remains in rest according to the Newton's first law of motion.

where:
 initial velocity of the student
 initial velocity of the student
velocity of the student after throwing the book:
Since the student applies a force on the book while throwing it and the student standing on the skate will an elastic collision like situation on throwing the book.

where:
 final velcotiy of the student after throwing the book
 final velcotiy of the student after throwing the book
b)



c)
Since there is no movement of the student in the vertical direction, so the total momentum transfer to the earth will be equal to the momentum of the book in vertical direction.



 
        
             
        
        
        
Answer:
True
Explanation:
Going even smaller than atoms would get you to subatomic particles such as quarks. From there, it is impossible to distinguish elements. So, yes, atoms are the smallest portions of an element that retains the original characteristic of the element.
 
        
             
        
        
        
1 m/s
Explanation:
To solve this question we use the following formula:
momentum = mass × velocity
momentum of the first car = 1000 kg × 2.5 m/s 
momentum of the second car = 2500 kg × X m/s
To bring the cars at rest the momentum of the first car have to be equal to the momentul of the second car.
momentum of the first car = momentum of the second car 
1000 kg × 25 m/s = 2500 kg × X m/s
X (velocity of the second car) = (1000 × 25) / 2500 = 1 m/s
Learn more about:
momentum
brainly.com/question/13378780
#learnwithBrainly
 
        
             
        
        
        
Answer:
P = 180 [w]
Explanation:
To solve this problem we must use ohm's law, which is defined by the following formula.
V = I*R & P = V*I
where:
V = voltage = 200[volts]
I = current [amp]
R = resistance [ohm]
P = power [watts]
Since the bulbs are connected in series, the powers should be summed
P = 60 + 60 + 60
P = 180 [watts]
Now we can calculate the current
I = 180/200
I = 0.9[amp]
Attached is an image where we see the three bulbs connected in series, in the circuit we see that the current is the same for all the elements connected to the circuit.
And the power is defined by P = V*I
we know that the voltage is equal to 200[V], therefore
P = 200*0.9
P = 180 [w]