Answer: 0.25 seconds.
Explanation:
The yo-yo does 240 revolutions in one minute, and we know that one minute has 60 seconds, then the revolutions per second can be calculated as:
240 rev/60s = 4 rev/s, this will be the frequency of the yo-yo
The frequency is actually written as: f = 4 Hz = 4 s^-1
We want to find the period of this yo-yo.
The period is the duration of one cycle, and we have the relation:
f = 1/T
Where f is the frequency and T is the period, then:
T = 1/f
And we know the value of f, it is f = 4 s^-1
Then the period will be:
T = 1/(4 s^-1) = (1/4) s
Then the period of the yo-yo is 1/4 seconds = 0.25 seconds.
Answer:

Explanation:
The final velocity is given by the following kinematic equation:

Here,
is the initial velocity, a is the body's acceleration and t is the motion time. We have to convert the time to seconds:

Now, we calculate the final velocity:

Answer:
Personally I say the yellow truck but...
Explanation:
It's heavily based on the object's mass...
If you know which object has the most mass than I would choose that one, but personally I think the yellow one has the most mass...
Answer:
The internal energy of a substance is equal to the total amount of potential energy and kinetic energy of ALL the particles in the substance.
For example, when the temperature increases (more temperature means more energy), the kinetic energy of the particles in the substance increases.
And when we reach a point near a change of phase (like near fusion point) there is energy used to break the bonds between the particles, then we have an increase in potential energy.
Then we could write the internal energy as:
U = ∑(KEₙ) + ∑(PEₙ)
Where ∑(KEₙ) and ∑(PEₙ) are the sums of the kinetic energy and potential energy of all the particles in the substance.