A hockey puck slides across the ice at a con-
stant speed.
Which of the following is true?
1. The puck is moving and thus not in equi-
librium.
2. The puck can be considered neither at
rest nor in equilibrium.
3. It is in equilibrium.
4. None of these
5. The puck is at rest.
Yes, it is in mechanical equilibrium. There is no longer a force acting upon the puck, which is why it remains at a constant speed. There was a force when the stick pushed it, and realistically there would be a very small force of friction which would slightly slow it down, but according to this question, the puck is not slowing down which means there is no friction. Mechanical equilibrium doesn't mean the object has to be at rest, it means that there is no acceleration or change in speed. Like Newton's law says; an object in motion will remain in motion if there are no forces acting upon it.
jsil
Set
To determine which statement is true, let's analyze the options:
1. The puck is moving and thus not in equilibrium.
Equilibrium refers to a state where all forces acting on an object are balanced. If the puck is sliding across the ice at a constant speed, it implies that there is no net external force acting on it. Therefore, option 1 is false.
2. The puck can be considered neither at rest nor in equilibrium.
If the puck is sliding at a constant speed, it may not be at rest but can still be in equilibrium if all the forces acting on it are balanced. So, option 2 is not entirely correct.
3. It is in equilibrium.
Based on the explanation in option 2, if the forces acting on the puck are balanced even though it's not at rest, it can still be in equilibrium. This means that option 3 can be considered the most accurate statement.
4. None of these.
Option 4 is incorrect since option 3, "It is in equilibrium," is a valid answer choice.
5. The puck is at rest.
Based on the initial information that the puck is sliding at a constant speed, we can conclude that the puck is not at rest. Therefore, option 5 is false.
So, the most accurate statement is option 3: "It is in equilibrium."
Common sense should enable you to eliminate some of these. How can it be sliding if it is at rest?
To be "at equilibrium" means that the net force acting is zero, in which case there is zero acceleration.
Now see if you can figure it out.