I would say 150 joules, i don't know if its right though check
        
                    
             
        
        
        
Answer:
...do
Explanation:
24. While measuring the length of a book, the reading of the scale at one end is 5.0 cm and at the other end is 20.5
cm. What is the length of the book in mm?
25. Explain the modifications
 
        
             
        
        
        
Answer:

Explanation:
We could use the following suvat equation:

where
s is the vertical displacement of the coin
v is its final velocity, when it hits the water
t is the time
g is the acceleration of gravity
Taking upward as positive direction, in this problem we have:
s = -1.2 m

And the coin reaches the water when
t = 1.3 s
Substituting these data, we can find v:

where the negative sign means the direction is downward.
 
        
             
        
        
        
Answer:
Explanation:
Acceleration acts for 9 s and deceleration acts for 12 - 9 = 3 s. 
Total distance covered = 990 m 
initial velocity u = o 
Distance covered while accelerating 
s₁ = 1/2 a 9² where a is the acceleration 
= 40.5 a 
final velocity after 9 s 
v = at = 9a
while decelerating 
v² = u² - 5 x s₂
0 = (9a)² - 5 s₂
s₂ = 16.2 a²
Distance covered while decelerating = 16.2 a²
s₁ + s₂ = 990 
40.5 a + 16.2 a² = 990
16.2 a² + 40.5 a - 990 = 0 
a = 6.5