Conceptual question regarding net force and velocity

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An object moving to the right with a decreasing net force will continue to accelerate to the right, but at a decreasing rate. The key point is that as long as the net force remains positive, the object will increase in speed, even if the force's magnitude is lessening. The confusion arises from the interpretation of decreasing force, which does not imply a negative acceleration unless the force becomes zero or negative. Therefore, the correct answer is that the object continues to move to the right with increasing speed, albeit at a decreasing rate. Understanding Newton's second law clarifies that acceleration is directly related to net force, regardless of its decreasing magnitude.
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Homework Statement



An object is moving to the right in a straight line. The net force acting on the object is also directed to the right, but the magnitude of the force is decreasing with time. The object will

a) stop and then begin moving to the left.
b) continue to move to the right, with its speed decreasing with time.
c) continue to move to the right, with its speed increasing with time.
d) continue to move to the right with a constant speed.

The answer is c)

Homework Equations





The Attempt at a Solution



My question is, can an object INCREASE in speed to the right at a DECREASING rate?

If so, then I understand why the answer is c) However, I thought if an object was moving to the right and the net force was also moving to the right, that would mean the object was increasing, and since the net force is decreasing with time, then shouldn't that change how the object is moving? like doesn't that mean the object will begin to decrease in speed?

Please explain to me the reason for the answer! (why it is c, and say, not b)

Thank-you for any help!
 
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physics120 said:
My question is, can an object INCREASE in speed to the right at a DECREASING rate?
Absolutely. As long as it moves to the right and it has an acceleration to the right, it's speed will increase. The rate at which the speed increases depends on the acceleration, which in turn depends on the net force.
 
Newton's second law: F=ma. What happens, if there is a force acting on the object and what happens when you take it off?

DocAl was faster! Damn!
 
Thanks Doc Al!
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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