Normal force during a push up problem

AI Thread Summary
The discussion revolves around calculating the normal force exerted by the floor on each hand during a push-up, given a person's weight of 633 N and specific distances from the center of gravity to the hands and feet. The user is attempting to set up equations based on the lever principle, using L1 and L2 as distances from the center of gravity to the hands and feet, respectively. They express confusion over the math involved in solving the equations and seek clarification on the diagram, which represents a side view of the person in the push-up position. The user confirms that the distances refer to the hands and feet, not the left and right hands. Overall, the thread highlights the challenges of applying physics concepts to real-life scenarios in biomechanics.
Max238
Messages
2
Reaction score
0
A person whose weight is W = 633 N doing push-ups.

l=====x====l==0
______ _____
0.885 0.358


Assume L1 = 0.885 m and L2 = 0.358 m. Calculate the normal force exerted by the floor on each hand, assuming that the person holds this position.

My work so far:
thinking L1 + L2 = 633
and .358Rhands=.885Rfeet; Rhands and Rfeet x and y respectivelyl

with a little substitution .358(633-x)=.885x
What I am having trouble is the simple math of solving this. I'm either doing something illogical or can't do simple math.
If this is wrong please tell me, if not what do I do? Maybe I've just been working on this problem a little too long...
 
Physics news on Phys.org
I don't understand the diagram. Are the two positions those of his right and left hands or those of his hands and his feet?
 
they are the hands and feet
you are seeing a sideview of the person with the x being his center of gravity
sorry
 

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

Work done by a normal force (or rather, work NOT done)
2
Replies
57
Views
4K
Calculating Force to Push Steel Rod Up 50 cm
Replies
24
Views
3K
Calculating Normal Forces in a Push-Up Position
Replies
9
Views
5K
Elevator Problem: What is the Normal Force Acting on a Person?
Replies
14
Views
2K
Normal force for stacked objects in a moving elevator
Replies
5
Views
4K
The maximal normal force (Friction with slanted surface)
Replies
18
Views
2K
Help with finding Normal Force of inclined plane
Replies
1
Views
3K
Normal Force of an object being pushed
Replies
1
Views
5K
Calculating Normal Force Exerted by Floor on Feet/Hands
Replies
1
Views
5K
Solving a Problem: Forces Acting on P
Replies
5
Views
1K

Hot Threads

Recent Insights

Back
Top