1) 1.08 m/s^2
Explanation:
Acceleration is equal to the change in velocity divided by the time taken:

where
v is the final velocity
u is the initial velocity
is the time taken
In this problem, we have:
- initial velocity: u = 0 (you start from rest)
- final velocity: v = 5.4 m/s
- time taken: 
Therefore, the acceleration is

2) -0.54 m/s^2
We can calculate the acceleration to slow down using the same formula as before, but this time the data are as follows:
- initial velocity : u = 5.4 m/s
- final velocity : v = 0 (you come to a stop)
- time taken : 
using the same formula, we find

And the negative sign means it is a deceleration.
Answer:
<em>The block hits the ground at 27.9 m/s</em>
Explanation:
<u>Gravitational Potential Energy (GPE)</u>
It's the energy stored in an object because of its height in a gravitational field.
It can be calculated with the equation:
U=m.g.h
Where m is the mass of the object, h is the height with respect to a fixed reference, and g is the acceleration of gravity or
.
When the block is at the edge of the cliff it has potential energy that can be transformed into any other type of energy as it starts falling to the ground.
The GPE of the block of mass m=42 Kg at h=40 m is:
U = 42*9.8*40
U = 16,464 J
The block loses 81 J due to air resistance, thus the energy stored when it hits the ground is 16,464 J - 81 J = 16,383 J.
This energy is stored as kinetic energy, whose formula is:

Solving for v:



v = 27.9 m/s
The block hits the ground at 27.9 m/s
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