The first thing you should know for this case is that density is defined as the quotient between mass and volume.
d = m / v
We have two states:
State 1:
d1 = 1.20 g / l
v1 = 1.02 × 106 l
State 2:
v2 = 1.09 × 106 l
Since the mass remains constant, then:
m = d1 * v1
Then, the density in state two will be:
d2 = m / v2
Substituting the value of the mass we have:
d2 = (d1 * v1) / v2
Substituting the values:
d2 = ((1.20) * (1.02 * 10 ^ 6)) / (1.09 * 10 ^ 6) = 1.12 g / l
answer:
The density of the heated air in the balloon is 1.12 g / l
The correct answer is
A. The mechanical energy transforms to thermal energy as the pendulum slows and eventually stops moving.
In fact, we must keep in mind the presence of the air, which causes some resistance to the motion of the pendulum. As the pendulum moves through the air, part of its mechanical energy is transferred to the molecules of air because of the friction of this molecules with the surface of the pendulum. As a result, the pendulum slows down, and eventually stops. The initial energy of the pendulum has been converted into thermal energy of the molecules of air, which move faster now.
The equivalent of Newton's second law for rotational objects is given by:
where
is the net torque acting on the object
is its moment of inertia
is its angular acceleration
For a hoop rotating around its perpendicular axis, the moment of inertia is
where m is the mass and r the radius. By using the data of the wheel, m=0.750 kg and r=33.0 cm=0.33 m, we find
and since the torque is
, the angular acceleration of the wheel is
Answer:
8 cm
Ladder is safer than to walk on it
Explanation:
Streched = Final length - initial length
= 66 - 58
= 8 cm
When your are walking along frozen ice pond your weight is not distributed .It's acting on directly on the ice pond because of contact Area is too small between pond and you. There for According to pressure equation ,
P = F/A
When area is less pressure is less.
If use ladder instead of going by foot. Contact area will be high between pond and ladder. There for pressure is reduced .
Answer:
T= 4.24sec
Explanation:
We are going to use the formula below to calculate.
Where T is period
L is length of rod
g is acceleration due to gravity =
From the problem, the rod is pivoted at 1/4L which means that three quarter of the rod was used for the oscillation. lets call this
= 4.4625m
thus
T= 4.24sec