Torque & Rotational Motion Question

Click For Summary
The discussion revolves around a physics problem involving torque and rotational motion related to a diver on a diving board. The diver experiences a force of 1,200 N at a 90-degree angle, creating clockwise torque, while their weight generates counterclockwise torque. The net torque is given as 2,985 N*m clockwise, leading to confusion about whether this should be considered negative. Participants question the clarity of the problem, particularly regarding the reference point for torque and the relevance of the diving board's length to the forces acting on the diver. Overall, the conversation highlights the complexities of understanding torque in this context.
Cheapo2004
Messages
9
Reaction score
0
Ok, here's a problem on a quiz that i just can't figure out. I'm having trouble drawing it in the first place:
-----------
At the moment before a diver jumps from a diving board, a force of 1.200 X 10^3 N is exerted on teh diver at an angle of 90 degrees to the board. This force produces a torque in the clockwise direction. At the same time, the diver's weight produces a torque in the counterclockwise direction. The diver's mass is 60 kg, and the angle between the diver's weight and the board is 87.7 degrees. If the net torque acting on the diver is 2985 N*m clockwise, what is the length of the diving board?
------------

For the first part, doesn't my teacher mean NEGATIVE 2985 N because its in the clockwise direction?
Anyways, here's the info i got out of that:

Tnet = 2985 N*m
F1 = 1200 N
F2 = ?
Degrees1 = 90
Degrees2 = 87.7

Any ideas about what equations i could use for this, or what it even looks like?!
 
Physics news on Phys.org
BUMP

Still need help :frown:
 
Cheapo2004 said:
Ok, here's a problem on a quiz that i just can't figure out. I'm having trouble drawing it in the first place:
-----------
At the moment before a diver jumps from a diving board, a force of 1.200 X 10^3 N is exerted on teh diver at an angle of 90 degrees to the board. This force produces a torque in the clockwise direction. At the same time, the diver's weight produces a torque in the counterclockwise direction. The diver's mass is 60 kg, and the angle between the diver's weight and the board is 87.7 degrees. If the net torque acting on the diver is 2985 N*m clockwise, what is the length of the diving board?
------------

For the first part, doesn't my teacher mean NEGATIVE 2985 N because its in the clockwise direction?
Anyways, here's the info i got out of that:

Tnet = 2985 N*m
F1 = 1200 N
F2 = ?
Degrees1 = 90
Degrees2 = 87.7

Any ideas about what equations i could use for this, or what it even looks like?!
Are you sure you have stated the problem correctly? I can't draw it either. A force exerted on the diver can only produce a torque on the diver. Is the first stated force on the diver a force exerted by the board, or is it the total force acting on the diver? The divers weight acts on the diver and can only produce a torque on the diver. Torque is always in reference to some point of rotation. What point are we to use? The logical point is the diver's CM, in which case the weight produces no torque, so all of the torque is due to the first force, a force that can never be found unless we know the distance between the line of the force and the point of rotation. Even if we could find this force, torques applied to the diver have absolutely nothing to do with the length of the board. As stated, I am afraid this is nonsense.
 
Thread 'Correct statement about size of wire to produce larger extension'
The answer is (B) but I don't really understand why. Based on formula of Young Modulus: $$x=\frac{FL}{AE}$$ The second wire made of the same material so it means they have same Young Modulus. Larger extension means larger value of ##x## so to get larger value of ##x## we can increase ##F## and ##L## and decrease ##A## I am not sure whether there is change in ##F## for first and second wire so I will just assume ##F## does not change. It leaves (B) and (C) as possible options so why is (C)...

Similar threads

Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
30
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 22 ·
Replies
22
Views
3K
Replies
4
Views
1K
  • · Replies 18 ·
Replies
18
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K