The mass of the aeroplane is 300,000 kg.
<h3>What is Newton's second law of motion?</h3>
It states that the force F is directly proportional to the acceleration a of the body and its mass.
The law is represented as 
F =ma
where acceleration a = velocity change v / time interval t
Given is the aeroplane lands at a speed of 80 m/s. After landing, the aeroplane takes 28 s to decelerate to a speed of 10 m/s. The mean resultant force on the aeroplane as it decelerates is 750 000 N.
The force expression will be
F = mv/t
Substitute the values and we have
750000 = m x  (80 -10)/ 28
750,000 = m x 2.5
m = 300,000 kg
Thus, the mass of the aeroplane is 300,000 kg.
Learn more about Newton's second law of motion.
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Answer:
Equilibrium temperature will be 
Explanation:
We have given weight of the lead m = 2.61 gram 
Let the final temperature is T 
Specific heat of the lead c = 0.128
Initial temperature of the lead = 11°C
So heat gain by the lead = 2.61×0.128×(T-11°C)
Mass of the water m = 7.67 gram 
Specific heat = 4.184
Temperature of the water = 52.6°C
So heat lost by water = 7.67×4.184×(T-52.6)
We know that heat lost = heat gained
So 


 
        
             
        
        
        
Answer:
1) Magnesium metal/magnesium ion
2) Aluminum/aluminum ion
3)  Copper metal/copper(l) ion
Explanation:
The activity series is a series that shows the ease of reactivity of substances in an electrochemical cell.
The substances that are higher up in the series are more reactive in electrochemical cells.
Magnesium is the first element in the series that has the most negative redox potential  then followed aluminium.
Hence, according to Nernst, 
1) Magnesium metal/magnesium ion
2) Aluminum/aluminum ion
3)  Copper metal/copper(l) ion
 
        
             
        
        
        
Answer:
C: Variation in the value of g as the pendulum bob moves along its arc.
Explanation:
The formula for period of a simple pendulum is given by;
T = 2π√(L/g)
Where;
L is length
g is acceleration due to gravity 
Now, from this period equation, it is clear that the only thing that can affect the period of a simple pendulum are changes to its length and acceleration due to gravity.
Looking at the options, the only one that talks about either the length or gravity as being potential causes of the error is option C 
 
        
             
        
        
        
Answer:
a) t = 0.528 s
b) D = 1.62 m
Explanation:
given,
speed of the baseball = 3.75 m/s
angle made with the horizontal = 35°
height of the roof edge = 2.5 m
using equation of motion 



4.9 t² + 2.15 t - 2.5 = 0
on solving the above equation 
t = 0.528 s
b) D = v cos θ × t
 D = 3.75 × cos 35° ×0.528
D = 1.62 m