Answer:
11.8 m/s
Explanation:
At the top of the hill, there are two forces on the car: weight force pulling down (towards the center of the circle), and normal force pushing up (away from the center of the circle).
Sum of forces in the centripetal direction:
∑F = ma
mg − N = m v²/r
At the maximum speed, the normal force is 0.
mg = m v²/r
g = v²/r
v = √(gr)
v = √(9.8 m/s² × 14.2 m)
v = 11.8 m/s
The length of the pendulum is 0.087 m. Option d is correct.
<h3>What is Simple harmonic motion?</h3>
Simple harmonic motion is periodic motion caused by a restoring force that is proportionate to the deviation from equilibrium.
Simple harmonic motion is periodic motion but many other conditions are dependent.
The time period of the pendulum is found as;

The length of the pendulum is 0.087 m
Hence, option d is correct.
To learn more about the simple harmonic motion refer to the link;
brainly.com/question/17315536
#SPJ1
Answer:
The problem occurs with all spherical mirrors.
Spherical mirrors are practical up to about inches in diameter.
Reflecting telescopes use spherical mirrors for apertures up to about 4 ".
Larger aperture telescopes use parabolic mirrors to obtain sharp focus.
Prior to the discovery and elaboration of Copernicus with the theory of heliocentricism, which states that the sun is the center of the universe and that the planets orbit around it in a circular manner. The theory of geocentrism was first published by another astronomer and philosopher, Ptolemy. As a custom in the early years of the society, people already stood for the idea that the earth is the center of the universe which is easy to believe at that time given that their perspective shows that the sun moves when observed from earth's atmosphere.
Answer:
1keff=1k1+1k2
see further explanation
Explanation:for clarification
Show that the effective force constant of a series combination is given by 1keff=1k1+1k2. (Hint: For a given force, the total distance stretched by the equivalent single spring is the sum of the distances stretched by the springs in combination. Also, each spring must exert the same force. Do you see why?
From Hooke's law , we know that the force exerted on an elastic object is directly proportional to the extension provided that the elastic limit is not exceeded.
Now the spring is in series combination
F
e
F=ke
k=f/e.........*
where k is the force constant or the constant of proportionality
k=f/e
............................1
also for effective force constant
divide all through by extension
1) Total force is
Ft=F1+F2
Ft=k1e1+k2e2
F = k(e1+e2) 2)
Since force on the 2 springs is the same, so
k1e1=k2e2
e1=F/k1 and e2=F/k2,
and e1+e2=F/keq
Substituting e1 and e2, you get
1/keq=1/k1+1/k2
Hint: For a given force, the total distance stretched by the equivalent single spring is the sum of the distances stretched by the springs in combination.