Need help with hw momentum and collisions

AI Thread Summary
The discussion revolves around calculating the recoil speed of the Earth when a person jumps, emphasizing the conservation of momentum principle. The estimated recoil speed is approximately 10^-23 m/s, highlighting the minuscule effect of a human jump on the Earth's motion. Participants are encouraged to consider the mass and velocity of both the jumper and the Earth in their calculations. The key takeaway is that the common center of mass remains stationary, necessitating that the momentum of the jumper and the Earth balance each other. Understanding these concepts is crucial for solving the problem effectively.
ballahboy
Messages
34
Reaction score
0
i hav no clue how to do this problem...

How fast can you set the Earth moving? In particular, when you jump straight up as high as you can, you give the Earth a maximum recoil speed of what order of magnitude? Visualize the Earth as a perfectly solid object. In your solution state the physical quantities you take as data and the values you measure or estimate for them.

Can anyone help me with this?
btw, the answer should be about 10^-23m/s
 
Physics news on Phys.org
Remember that your common center of mass remains at rest at all times..
 
Your mass times velocity must equal the Earth's mass time velocity (but with opposite sign in order that the total remain 0.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Question about Momentum and Collisions
Replies
6
Views
1K
How Does Elastic Collision Affect Momentum and Force in Racquetball?
Replies
3
Views
4K
Railway/Cannon - Conservation of Momentum HW Problem
Replies
9
Views
2K
Initial velocity in an inelastic collision
Replies
4
Views
2K
I Conservation of momentum in a collision
2
Replies
67
Views
6K
I Question about Momentum vs. Kinetic Energy vs. Deforming In Collisions
Replies
2
Views
2K
Angular Momentum of Multiple Objects with Collision
Replies
2
Views
4K
Collision problems (Conservation of Momentum & Energy)
Replies
1
Views
7K
How Do You Prove the Law of Conservation of Momentum in Collisions?
Replies
10
Views
2K
Car collision: decomposing momentum in x- and y-direction
Replies
5
Views
9K

Hot Threads

Recent Insights

Back
Top