Answer:

Explanation:
From the second law of Newton movement laws, we have:
, and we know that a is the acceleration, which definition is:
, so:

The next step is separate variables and integrate (the limits are at this way because at t=0 the block was at rest (v=0):

(This is the indefinite integral), the definite one is:

Answer:
The wall is 680 meter away from the person.
Explanation:
Given data
Speed of sound = 340 
Given that Persons said hello toward the opposite side she has an echo hello 4 seconds later means it takes 2 seconds for the sound to reach the wall & again 2 seconds to reach the persons ear.
Therefore the distance between the person & wall is
D = speed × Time
D = 340 × 2
D = 680 meter
Therefore the wall is 680 meter away from the person.
Answer:
(X - 25)/Y
Explanation:
Change in velocity = X - 25
Time elapsed = Y
Acceleration = Change in velocity/Time = (X - 25)/Y
Initial kinetic energy = 0J (v=0 (rest))
Final kinetic energy = 1/2mv ²
Ek=1/2(9)(27 ²)
Ek=4.5(729)
Ek=3280.5
∆Energy=3280.5J
(As it starts from 0)
Work= ∆energy
So work =3280.5J
Answer=3300J (forth option)