Does a Slowing Piano Exert More Force Than the Man Pushing It?

In summary, the question explores the physics involved when a man pushes a piano that is slowing down. It examines the forces at play, including the impact of the piano's momentum and the push from the man. The analysis reveals that the force exerted by the man may not necessarily exceed the force required to decelerate the piano, depending on various factors like the mass of the piano and the speed at which it is moving. Ultimately, it highlights the interplay between force, mass, and acceleration in understanding the dynamics of the situation.
  • #1
mancity
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Homework Statement
A piano is rolling down a frictionless slope at an ever increasing speed. The piano tuner sees it, slowing it down to a constant speed. The magnitude of the force on the man by the piano is F_MP; the magnitude of the force on the man by the man is F_PM. If we compare these forces, we find
(A) F PM > F MP always.
(B) F PM > F MP while the piano slows down but F PM = F MP when the piano is moving at constant speed.
(C) F PM = F MP always.
(D) F PM = F MP while the piano slows down but F PM > F MP when the piano is moving at constant speed.
Relevant Equations
Newton's third law
Albeit the simple question, I am a bit confused on whether the correct answer choice is (B) or (C). When the piano is slowing down, shouldn't the force received by the piano be a bit greater than the force received by the man?
 
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  • #2
What does Newton III say?
Why do you think otherwise?
 
  • #3
mancity said:
Homework Statement: A piano is rolling down a frictionless slope at an ever increasing speed. The piano tuner sees it, slowing it down to a constant speed.
If the slope is frictionless the piano tuner will slide and will be unable to slow down the piano.
 
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  • #4
mancity said:
When the piano is slowing down, shouldn't the force received by the piano be a bit greater than the force received by the man?
Draw well-separated free-body diagrams of piano and the man. Note that the net force on both the man and the piano are nonzero.
 

FAQ: Does a Slowing Piano Exert More Force Than the Man Pushing It?

Does the piano exert more force on the man as it slows down?

As the piano slows down, the force exerted by the piano on the man depends on the interaction between the two. If the man is actively pushing to slow it down, the force exerted by the piano on the man can be significant, but it is usually less than the force the man applies to decelerate it.

What role does friction play when a piano is slowing down?

Friction plays a crucial role in slowing down the piano. The frictional force between the piano and the ground, as well as between the man’s hands and the piano, opposes the motion of the piano and helps in decelerating it. The man’s push also contributes to overcoming this frictional force.

How can we calculate the force exerted by the man on the piano?

The force exerted by the man on the piano can be calculated using Newton's second law, F = ma, where 'F' is the force, 'm' is the mass of the piano, and 'a' is the acceleration (which will be negative if the piano is decelerating). Additionally, the force of friction should be considered in the total force calculation.

Why might it seem like the piano exerts more force than the man pushing it?

It might seem like the piano exerts more force because of its large mass and the resistance to change in motion (inertia). When the man pushes against the piano to slow it down, the reaction force from the piano can feel substantial due to its weight and the effort required to decelerate it.

Is the force exerted by the man always greater than the force exerted by the piano?

No, the forces are equal in magnitude but opposite in direction according to Newton's third law of motion. The man exerts a force on the piano to slow it down, and the piano exerts an equal and opposite force on the man. However, the man's force is directed to decelerate the piano, while the piano's force is a reaction to this push.

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