Answer:
because the mass of the apple is very less compared to the mass of earth. Due to less mass the apple cannot produce noticable acceleration in the earth but the earth which has more mass produces noticable acceleration in the apple. thus we can see apple falling on towards the earth but we cannot see earth moving towards the apple.
What if I don’t give you the answer
Answer:
15√2 N
Explanation:
The acceleration is given by ...
a = F/m = 5t/5 = t . . . . meters/second^2
The velocity is the integral of acceleration:
v = ∫a·dt = (1/2)t^2
This will be 9 m/s when ...
9 = (1/2)t^2
t = √18 . . . . seconds
And the force at that time is ...
F = 5(√18) = 15√2 . . . . newtons