Study the scenario.
An object is at rest. At five seconds, someone comes over and pushes the object with a force of 3 N to the right.
Which of the following choices describes the force needed to keep the object in static equilibrium?
a. A force of 3 N to the left must be exerted on the box at any time after 5 seconds so that the forces are balanced and the object moves at constant velocity.
b. A force of 3 N to the left must be exerted on the box at exactly 5 seconds, so that the forces are balanced and the object remains at rest.
c. There is no way to keep the object in static equilibrium once the person exerts the 3 N force on the box.
d. A force greater than 3 N to the left must be exerted on the object at exactly 5 seconds to prevent the object from moving.
I Know 100% that it isn't A and I don't think it is C so do you think it could be B?
"static" equilibrium means that the object remains at rest
... the forces must cancel each other , and be applied simultaneously
B looks good
To determine the correct choice, let's analyze the scenario and the concept of static equilibrium.
Static equilibrium refers to a condition where an object is at rest or moving at a constant velocity with no net force acting on it. In this scenario, an object is initially at rest, and at five seconds, someone exerts a force of 3 N to the right. To keep the object in static equilibrium, there must be a balance of forces.
Let's examine each option:
a. A force of 3 N to the left must be exerted on the box at any time after 5 seconds so that the forces are balanced and the object moves at a constant velocity.
This option is incorrect because it states that the object moves at a constant velocity, which contradicts the condition of static equilibrium where the object must be at rest or moving with zero acceleration.
b. A force of 3 N to the left must be exerted on the box at exactly 5 seconds so that the forces are balanced and the object remains at rest.
This option is correct. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. So, to maintain static equilibrium, a force of the same magnitude (3 N) but in the opposite direction must be exerted on the object. This opposing force of 3 N to the left will balance the initial force applied to the right, keeping the object at rest.
c. There is no way to keep the object in static equilibrium once the person exerts the 3 N force on the box.
This option is incorrect. Static equilibrium can be achieved by applying a force in the opposite direction to balance the initial force, as mentioned above.
d. A force greater than 3 N to the left must be exerted on the object at exactly 5 seconds to prevent the object from moving.
This option is incorrect. To maintain static equilibrium, the force applied must be equal in magnitude but opposite in direction, so a force greater than 3 N is not required.
Based on our analysis, the correct choice is b. A force of 3 N to the left must be exerted on the box at exactly 5 seconds so that the forces are balanced and the object remains at rest.