Answer:
The correct answer to the question is
B. It always decreases
Explanation:
To solve the question, we note that the foce of gravity is given by
where
G= Gravitational constant
m₁ = mass of first object
m₂ = mass of second object
r = the distance between both objects
If the mass of one object remains unchanged while the distance to the second object and the second object’s mass are both doubled, we have
=
Therefore the gravitational force is halved. That is it will always decrease
Answer:
The speed of the train before and after slowing down is 22.12 m/s and 11.06 m/s, respectively.
Explanation:
We can calculate the speed of the train using the Doppler equation:
Where:
f₀: is the emitted frequency
f: is the frequency heard by the observer
v: is the speed of the sound = 343 m/s
: is the speed of the observer = 0 (it is heard in the town)
: is the speed of the source =?
The frequency of the train before slowing down is given by:
(1)
Now, the frequency of the train after slowing down is:
(2)
Dividing equation (1) by (2) we have:
(3)
Also, we know that the speed of the train when it is slowing down is half the initial speed so:
(4)
Now, by entering equation (4) into (3) we have:
By solving the above equation for we can find the speed of the train after slowing down:
Finally, the speed of the train before slowing down is:
Therefore, the speed of the train before and after slowing down is 22.12 m/s and 11.06 m/s, respectively.
I hope it helps you!
Answer:
A skater glides along a circular path. She defines a certain point on the circle as her origin. Later on, she passes through a point at which the distance she has traveled along the path from the origin is smaller than the magnitude of her displacement vector from the origin.
So here in circular motion of the skater we can see that the total path length of the skater is along the arc of the circle while we can say that displacement is defined as the shortest distance between initial and final position of the object.
So it is not possible in any circle that arc-length is less than the chord joining the two points on the circle
As we know that arc length is given as
length of chord is given as
so here
so we have
