A mechanical wave can only travel through matter.
Answer:0.302
Explanation:
Given
mass of crate m=27 kg
Force required to set crate in motion is 80 N
Once the crate is set in motion 56 N is require to move it with constant velocity
i.e. 80 N is the amount of force needed to just overcome static friction and 56 is the kinetic friction force
thus

where
is the coefficient of static friction and N is Normal reaction





They both are two different elements.SO the answer is Element
With constant angular acceleration
, the disk achieves an angular velocity
at time
according to

and angular displacement
according to

a. So after 1.00 s, having rotated 21.0 rad, it must have undergone an acceleration of

b. Under constant acceleration, the average angular velocity is equivalent to

where
and
are the final and initial angular velocities, respectively. Then

c. After 1.00 s, the disk has instantaneous angular velocity

d. During the next 1.00 s, the disk will start moving with the angular velocity
equal to the one found in part (c). Ignoring the 21.0 rad it had rotated in the first 1.00 s interval, the disk will rotate by angle
according to

which would be equal to

The data given in the bar graph is valid because it follows the law of conservation of energy, since the GPE at top of 2nd hill plus KE at top of 2nd hill equals KE at bottom of 1st hill.
<h3>What is law of conservation of energy?</h3>
The law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another.
Based on the law of conservation of energy, kinetic energy of a roller coaster can be converted into potential energy of the roller coaster and vice versa.
ΔK.E = ΔP.E
where;
- ΔK.E is change in kinetic energy
- ΔP.E is change in potential energy
The kinetic energy of the coaster is greatest at the bottom of the hill, as the coaster moves upward, the kinetic energy decreases and will be converted into potential energy. The potential energy of the coaster increases as the coaster moves up the hill and will become maximum at the highest point of the hill.
From the given data;
GPE at top of 2nd hill + KE at top of 2nd hill = KE at bottom of 1st hill
Learn more about conservation of energy here: brainly.com/question/166559
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