Answer:
259.52N
Explanation:
Force initiated on a spring that causes an extension is related by the expression below;
F= K×e
Where F is the Force
K is the spring constant
e is the extension caused by the spring.
By change of subject formula for K;
K = F/e
Now F is the same as weight and is given by mass× acceleration. In this case acceleration is g=9.8m/s2; this is because the child's mass is going to be under the influence of gravity as it swings up the harness}
Hence W =7.15×9.8=70.07N
Hence K = 70.07/0.27 =259.5185N/m
=259.52N/m to 2 decimal place.
Answer:
The maximum speed at which the car can safety travel around the track is 18.6m/s.
Explanation:
Since the car is in circular motion, there has to be a centripetal force 
. In this case, the only force that applies for that is the static frictional force 
between the tires and the track. Then, we can write that:
And since 
and 
, we have:
Now, if we write the vertical equation of motion of the car (in which there are only the weight and the normal force), we obtain:
Substituting this expression for 
and solving for 
, we get:
Finally, plugging in the given values for the coefficient of friction and the radius of the track, we have:
It means that in its maximum value, the speed of the car is equal to 18.6m/s.
The statement "<span>Atomic physicists do not know why all of the atomic particles stay together within an atom" is false. In fact, physicists now knows why they are concentrated within an atom. It is because of the opposite charges between the electrons and protons.</span>
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