Answer:
a = 7.29 m / s², T = 0.40 N
Explanation:
To solve this exercise we must apply Newton's second law to each body
The needle
W -T = m a
mg - T = ma
The spool, which we will approach by a cylinder
Σ τ = I α
T R = I α
the moment of inertia of a cylinder with an axis through its center is
I = ½ M R²
angular and linear variables are related
a = α R
α = a / R
we substitute
T R = (½ M R²) a / R
T = ½ M a
we write our system of equations together
mg - T = m a
T = ½ M a
we solve
m g = (m + ½ M) a
a = 
let's calculate
a = 
a = 7.29 m / s²
now we can look for the tension
T = ½ M a
T = ½ 0.110 7.29
T = 0.40 N
Democritus was a Greek philosopher who lived between 470-380 B.C. He developed the concept of the 'atom', Greek for 'indivisible'. Democritus believed that everything in the universe was made up of atoms, which were microscopic and indestructible. Democritus had many remarkable insights for his time.
I think the answer is D, but I’m not at all sure :l
Answer:
y₀ = 10.625 m
Explanation:
For this exercise we will use the kinematic relations, where the upward direction is positive.
y = y₀ + v₀ t - ½ g t²
in the exercise they indicate the initial velocity v₀ = 8 m / s.
when the rock reaches the ground its height is zero
0 = y₀ + v₀ t - ½ g t²
y₀i = -v₀ t + ½ g t²
let's calculate
y₀ = - 8 2.5 + ½ 9.8 2.5²
y₀ = 10.625 m
Answer:
A
Explanation:
<em>The gold used in the making of jewelry is usually not pure but a heterogeneous mixture of metals. Pure gold is quite soft and even though it may look better in appearance compared to those made using heterogeneous mixtures, it usually bends easily. Hence, in order to make the jewelry more durable, gold is usually mixed with other metals to form a heterogeneous mixture. </em>
The correct option is A.
