The net force must be zero
This is in accordance to Newton's first law, which states that any object in motion will remain in motion and any object at rest will remain at rest unless acted upon by an unbalanced force. An unbalanced force is one where the net force is not zero. If no unbalanced force is applied to a moving object, it will keep moving forever. The reason that we do not observe this in our daily lives is due to friction acting as the unbalanced force.
        
             
        
        
        
Answer:
c and d
Explanation:
obviously kksxsxksxkskxkskxksxksxsxsxsxsxsxsxs
 
        
             
        
        
        
Given that,
Time = 0.5 s
Acceleration = 10 m/s²
(I). We need to calculate the speed of apple
Using equation of motion

Where, v = speed
u = initial speed
a = acceleration
t = time
Put the value into the formula


(III). We need to calculate the height of the branch of the tree from the ground
Using equation of motion

Put the value into the formula


(II). We need to calculate the average velocity during 0.5 sec
Using formula of average velocity


Where, 
= final position
 = initial position
Put the value into the formula


Hence, (I). The speed of apple is 5 m/s.
(II). The average velocity during 0.5 sec is 2.5 m/s
(III). The height of the branch of the tree from the ground is 1.25 m.
 
        
             
        
        
        
Answer:
F. 25.82 s
Explanation:
Given:
Δy = 90 m
v₀ = 0 m/s
a = 0.27 m/s²
Find: t
Δy = v₀ t + ½ at²
90 m = (0 m/s) t + ½ (0.27 m/s²) t²
t = 25.82 s