A baby slides an empty box across the floor. If the baby puts wooden blocks into the box and continues to slide it, what happens to the force of kinetic friction?

A
It decreases.

B
It increases.

C
It remains the same.

D
It is halved.

Topic Flashcards

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Question

What is the formula for calculating the force of kinetic friction (F_k), and what does each variable represent?

Answer

F_k = μ_k * N, where μ_k is the coefficient of kinetic friction (a property of the surfaces), and N is the normal force (the force pressing the surfaces together, often equal to weight on a flat surface).

Question

How does adding mass to the box sliding on a flat floor change the normal force (N), and why?

Answer

Adding mass increases the weight of the box. On a flat floor, the normal force is equal and opposite to the weight. Therefore, increasing the mass increases the normal force (N).

Question

Assuming the floor and box material don't change, what two things must you know to calculate the new force of kinetic friction after blocks are added?

Answer

You must know the coefficient of kinetic friction (μ_k), which remains constant, and the new total mass (to calculate the new normal force: N = m*g)

Question

If the original empty box had a kinetic friction force of 5 N, and adding blocks doubled its total mass, what is the new friction force (assuming the same surface)?

Answer

Doubling the mass doubles the normal force (N). Since F_k ∝ N, the kinetic friction force also doubles to 10 N.

Question

Why does the force required to push the box at a constant speed also increase when blocks are added?

Answer

To keep an object moving at constant velocity, the applied force must exactly balance the kinetic friction force. Since adding blocks increases the kinetic friction, the required pushing force must increase by the same amount.

Mini Quiz

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Does the force of kinetic friction depend on the speed at which the box is sliding (for typical speeds)?

A baby slides an empty box across the floor. If the baby puts wooden blocks into the box and continues to slide it, what happens to the force of kinetic friction?

A
It decreases.

B
It increases.

C
It remains the same.

D
It is halved.

The force of kinetic friction increases.

Topic Flashcards

Mini Quiz

Related Questions

A baby slides an empty box across the floor. If the baby puts wooden blocks into the box and continues to slide it, what happens to the force of kinetic friction?

A It decreases. B It increases. C It remains the same. D It is halved.

The force of kinetic friction increases.

Topic Flashcards

Mini Quiz

Related Questions

A
It decreases.

B
It increases.

C
It remains the same.

D
It is halved.