Calculating Mass and Gravity on Planet Newtonia

AI Thread Summary
On planet Newtonia, a pendulum with a mass of 1.00 and a length of 195.0 takes 1.40 seconds to swing through an angle of 12.5 degrees. The user calculated gravitational acceleration (g) using the formula T = 2pi*sqrt(L/g) but struggled to find the planet's mass using g, the gravitational constant (G), and the radius derived from the planet's circumference of 51400. It was clarified that the angle does not significantly affect the calculations as long as it is small, like 12.5 degrees. The user was reminded that the period T represents two swings, which contributed to the confusion. Accurate calculations are essential for determining mass and gravity on Newtonia.
pdiddy94
Messages
2
Reaction score
0
On the planet Newtonia, a simple pendulum having a bob with mass 1.00 and a length of 195.0 takes 1.40 , when released from rest, to swing through an angle of 12.5 , where it again has zero speed. The circumference of Newtonia is measured to be 51400 .

I solved for g using T = 2pi*sqrt(L/g) and then i used this g plus the constant G and the radius solved from the given circumference to calculate the mass of the planet from the equation g = GM/R^2 but can't get the answer, i don't know if its because I'm not taking the angle into account?
 
Physics news on Phys.org
welcome to pf!

hi pdiddy94! welcome to pf! :smile:
pdiddy94 said:
… takes 1.40 , when released from rest, to swing through an angle of 12.5 , where it again has zero speed.
…
… i don't know if its because I'm not taking the angle into account?

the angle makes no difference (so long as it's reasonably small, as 12.5° is),

but the period T is for two swings, isn't it? :wink:
 
ohh, thank you that makes sense
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggle to understand the concept of the question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

How to find the acceleration due to gravity inside a planet?
Replies
3
Views
5K
Acceleration of Planet/Sun System
Replies
3
Views
1K
Gravitational Potential Energy questions near the surface of a planet
Replies
8
Views
2K
Calculating the velocity of a head-on impact between two suns
Replies
6
Views
2K
Experimental Design: Pulley and Mass Hangers
Replies
30
Views
3K
Small oscillation frequency of rod and disk pendulum
Replies
5
Views
2K
Pressure Halfway through a planet
Replies
4
Views
3K
Foucault Pendulum at the North Pole
Replies
9
Views
2K
Determine the mass of the planet using Newton’s Law of Universal Gravitation
Replies
2
Views
3K
Calculate the Orbital Radius of a Planet
Replies
1
Views
9K

Hot Threads

Recent Insights

Back
Top