Answer:
The acceleration of man 1 and 2 is
and
.
Explanation:
Mass of man 1, m₁ = 80 kg
Mass of man 2, m₂ = 60 kg
One man pulls on the rope with a force of 250 N.
Let a₁ is acceleration of man 1,
F = m₁a₁

Let a₂ is acceleration of man 1,
F = m₂a₂

So, the acceleration of man 1 and 2 is
and
.
Connection to Big Idea about energy: Gravity creates gravitational potential energy. Gravitational energy relies on the masses of two bodies and their distance.
Connection to Big Idea about the universe: Gravitational force is exerted by all objects with mass throughout the Universe. It is what keeps the Earth and the planets in orbit around the Sun, and our Solar System in orbit around the centre of the Milky Way. Gravity is one of the forces involved in the birth of stars, their evolution and finally their death.
Connection to Big Idea about Earth: The gravitational force is responsible for many physical properties of Earth and consequently it affects the existence and the properties of living creatures on it. For instance, the existence, the chemical composition and the structure of Earth’s atmosphere was determined by Earth’s gravitational force.
Answer:

Explanation:
According to the free body diagram, in this case, we have:

Recall that the force of friction is given by:

Replacing and solving for the coefficient of kinetic friction:

We have an uniformly accelerated motion. Thus, the acceleration is defined as:

Finally, we calculate
:
