Find the time required to to cover the length of the tunnel.

[npgreat]

A tunnel is dug through the centre of the earth.A particle is projected into it with a velocity =(gR)^1/2.Find the time required to to cover the length of the tunnel.
The force of attraction is F=GMmx/R^3 where x=distance from centre
Then the time period is T=2*3.14*(R^3/GM)^1/2
And the answer comes out to be Half of the time period
But I am not understanding what to do with the initial velocity.

 

[stunner5000pt]

Perhaps you should us some of your attempted work? then maybe someone would approach. But since I am nice and all


yes it is simple harmonic motion so then in general SHM equation is
$$m \frac{d^2 r}{dt^2} + b \frac{dr}{dt} + kr = F$$

since this is tunnel taht doesn't depend on its sides no b and certainly no F value. All you're left with a k value.

sooo you're left with what?? What is the k?
Here that radial distance is not constant! Instead The k value is dependant on the distnace form thcentre of the earth. See how you could fit your gravitational force formula into the k value. after you have k you can figure out the period, can't you??

 

[thepatientmental]

The initial velocity is important to consider in this scenario as it will affect the time required for the particle to cover the length of the tunnel. The formula for time period that you have mentioned is for a simple harmonic motion, which may not be applicable in this situation. In order to calculate the time required, we need to take into account the initial velocity of the particle and the acceleration due to gravity as it travels through the tunnel.

To find the time required, we can use the formula t = √(2d/g), where t is the time, d is the distance (in this case, the length of the tunnel), and g is the acceleration due to gravity. However, since the force of attraction (F) in this scenario is inversely proportional to the square of the distance (x) from the center, we can rewrite the formula as t = √(2x^3/GMm).

Therefore, to find the time required, we need to know the initial velocity (v) and the distance (x) from the center of the earth. The initial velocity can be calculated using the formula v = √(gR), where R is the radius of the earth and g is the acceleration due to gravity on the surface of the earth.

Once we have the initial velocity and the distance from the center, we can plug them into the formula t = √(2x^3/GMm) to find the time required for the particle to cover the length of the tunnel. It is important to note that this calculation assumes a constant acceleration due to gravity and ignores any other factors such as air resistance or the changing force of gravity as the particle moves through the tunnel.