Answer:
P = 2.45 N
Q = 6.65 N
Explanation:
According to Newton's 2nd Law:
Unbalanced Force = ma
where,
m = mass = 7 kg
a = acceleration
In the first case when both forces P and Q act on left side:
Unbalanced Force = P + Q
a = 1.3 m/s²
Therefore,
P + Q = (7 kg)(1.3 m/s²)
P + Q = 9.1 N ------------------------- equation 1
Now, in second case when both forces have different directions:
Unbalanced Force = Greater Force - Smaller Force
Unbalanced Force = Q - P
a = 0.6 m/s²
Therefore,
Q - P = (7 kg)(0.6 m/s²)
Q - P = 4.2 N ------------------- equation 2
Adding equation 1 and equation 2, we get:
(Q + P) + (Q - P) = 9.1 N + 4.2 N
2 Q = 13.3 N
<u>Q = 6.65 N</u>
Using this value in equation 2, we get:
6.65 N - P = 4.2 N
<u>P = 2.45 N</u>
Answer: Find the answer in the explanation
Explanation:
The music playing on the radio will be heard through the sound waves coming from the radio.
The travelling wave will obey Newton's first law of motion which state that:
An object or particle will remain at rest or continue its linear motion in a straight line except an external force is applied.
The external force through wind could affect the travelling of the sound waves. Since the wave is longitudinal wave. That is, it needs a medium (air) for its propagation.
Taking into account the Newton's first Law, the correct answer is option C. To overcome an object's inertia, it must be acted upon by a force.
Newton's First Law, also called the Law of inertia, indicates that "Every body perseveres in its state of rest or of uniform rectilinear motion unless it is forced to change its state by forces impressed on it." This means that for a body to come out of its state of rest or of uniform rectilinear motion, it is necessary for a force to act on it.
In other words, it is not possible for a body to change its initial state (be it rest or motion) unless one or more forces intervene.
Finally, the correct answer is option C. To overcome an object's inertia, it must be acted upon by a force.
Learn more:
Answer:
5.327
Explanation:
Stefan-Boltzmann law states that the total radiant heat power emitted from a surface is proportional to the fourth power of its absolute temperature.
W = σT⁴
Where,
W is the total radiant heat power emitted from a surface
σ is constant of proportionality, called the Stefan–Boltzmann constant = 5.67 × 10⁻⁸ Wm⁻²K⁻⁴
T is absolute temperature in kelvin
For the first star, T = 5200 K
∴ W₁ = σ(5200)⁴
For the second star, T = 7900 K
∴ W₂ = σ(7900)⁴
The amount of energy radiated by the hotter star W₂, with respect to the other star W₁ is,
W₂ / W₁ = σ(7900)⁴ / σ(5200)⁴
This type of a problem can be solved by considering energy transformations. Initially, the spring is compressed, thus having stored something called an elastic potential energy. This energy is proportional to the square of the spring displacement d from its normal (neutral position) and the spring constant k:
So, this spring is storing almost 12 Joules of potential energy. This energy is ready to be transformed into the kinetic energy when the masses are released. There are two 0.2kg masses that will be moving away from each other, their total kinetic energy after the release equaling the elastic energy prior to the release (no losses, since there is no friction to be reckoned with).
The kinetic energy of a mass m moving with a velocity v is given by:
And we know that the energies are conserved, so the two kinetic energies will equal the elastic potential one:
From this we can determine the speed of the mass:
The speed will be 7.74m/s in in one direction (+), and same magnitude in the opposite direction (-).