In which situation would the momentum of a moving object increase?
A: A new force acts on the object, opposing the object’s motion.
B: A force acting in the direction opposite the object’s motion is removed from the object.
C: A force acting in the direction of the object’s motion is removed from the object.
D: Two forces of equal magnitude act on the object in opposite directions.
back in my day these websites had answers-
The correct answer is C: A force acting in the direction of the object’s motion is removed from the object.
Momentum is the product of an object's mass and velocity. According to the law of conservation of momentum, the total momentum of a system remains constant unless acted upon by an external force.
If a force acting in the direction of the object's motion is removed, the object will continue to move with the same velocity but with less resistance, resulting in an increase in momentum.
In contrast, options A and D describe situations where the momentum of the object would decrease, and option B describes a situation where the momentum would remain constant.
The situation in which the momentum of a moving object would increase is when a force acting in the direction of the object's motion is removed from the object. Option C: A force acting in the direction of the object’s motion is removed from the object.
To determine which situation would cause an increase in the momentum of a moving object, let's understand the concept of momentum first.
Momentum is the product of an object's mass and velocity and is defined as the quantity of motion an object possesses. Mathematically, momentum (p) is expressed as:
p = m * v
Now, let's analyze the different situations mentioned in the question:
A: A new force acts on the object, opposing the object’s motion.
In this situation, the force is opposing the object's motion, meaning it works against the velocity of the object. As momentum is directly proportional to velocity, if the force opposes the motion (velocity), it will reduce the object's momentum, not increase it. Therefore, this option does not contribute to an increase in momentum.
B: A force acting in the direction opposite the object’s motion is removed from the object.
Here, a force acting in the opposite direction of the object's motion is being removed. As a force in the opposite direction reduces the momentum, by removing it, the object can continue moving with its original velocity, resulting in an increase in momentum. Therefore, removing such a force will cause an increase in momentum.
C: A force acting in the direction of the object’s motion is removed from the object.
If a force acting in the direction of the object's motion is removed, the object will lose the additional force acting in the same direction as its motion. Consequently, the object will slow down and have a lower velocity, reducing its momentum. Therefore, removing such a force will not cause an increase in momentum.
D: Two forces of equal magnitude act on the object in opposite directions.
When two forces of equal magnitude act on an object in opposite directions, they cancel each other out. As a result, the object experiences a net force of zero, which means its velocity remains constant. Since momentum depends on velocity, keeping the same velocity means the momentum remains unchanged in this scenario.
To summarize, the situation where the momentum of a moving object would increase is when a force acting in the direction opposite to the object's motion (option B) is removed from the object.