Question

The weight of a rectangular block of low-density material is $15.0 \mathrm{~N}$. With a thin string, the center of the horizontal bottom face of the block is tied to the bottom of a beaker partly filled with water. When $25.0 \%$ of the block's volume is submerged, the tension in the string is $10.0 \mathrm{~N}$. (a) Find the buoyant force on the block. (b) Oil of density $800 \mathrm{~kg} / \mathrm{m}^{3}$ is now steadily added to the beaker, forming a layer above the water and surrounding the block. The oil exerts forces on each of the four sidewalls of the block that the oil touches. What are the directions of these forces? (c) What happens to the string tension as the oil is added? Explain how the oil has this effect on the string tension. (d) The string breaks when its tension reaches $60.0 \mathrm{~N}$. At this moment, $25.0 \%$ of the block's volume is still below the water line. What additional fraction of the block's volume is below the top surface of the oil?

          The weight of a rectangular block of low-density material is $15.0 \mathrm{~N}$. With a thin string, the center of the horizontal bottom face of the block is tied to the bottom of a beaker partly filled with water. When $25.0 \%$ of the block's volume is submerged, the tension in the string is $10.0 \mathrm{~N}$.
(a) Find the buoyant force on the block. 
(b) Oil of density $800 \mathrm{~kg} / \mathrm{m}^{3}$ is now steadily added to the beaker, forming a layer above the water and surrounding the block. The oil exerts forces on each of the four sidewalls of the block that the oil touches. What are the directions of these forces?
(c) What happens to the string tension as the oil is added? Explain how the oil has this effect on the string tension.
(d) The string breaks when its tension reaches $60.0 \mathrm{~N}$. At this moment, $25.0 \%$ of the block's volume is still below the water line. What additional fraction of the block's volume is below the top surface of the oil?

Show more…

Added by Victor L.

University Physics with Modern Physics

Hugh D. Young 14th Edition

Instant Answer

Solved by Expert Penny Riley

07/04/2022

Step 1

Step 1: Calculate the buoyant force on the block. Show more…

Show all steps

lock

Thanks for your feedback!

The weight of a rectangular block of low-density material is $15.0 \mathrm{~N}$. With a thin string, the center of the horizontal bottom face of the block is tied to the bottom of a beaker partly filled with water. When $25.0 \%$ of the block's volume is submerged, the tension in the string is $10.0 \mathrm{~N}$. (a) Find the buoyant force on the block. (b) Oil of density $800 \mathrm{~kg} / \mathrm{m}^{3}$ is now steadily added to the beaker, forming a layer above the water and surrounding the block. The oil exerts forces on each of the four sidewalls of the block that the oil touches. What are the directions of these forces? (c) What happens to the string tension as the oil is added? Explain how the oil has this effect on the string tension. (d) The string breaks when its tension reaches $60.0 \mathrm{~N}$. At this moment, $25.0 \%$ of the block's volume is still below the water line. What additional fraction of the block's volume is below the top surface of the oil?

Play audio

Feedback

Powered by NumerAI

Penny Riley and 99 other subject Physics 101 Mechanics educators are ready to help you.

Ask a new question

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Recommended Videos

Recommended Textbooks

Transcript

00:01 Find the buoyant force of this block.

00:03 So let's draw a free body diagram.

00:06 In our free body diagram, we have our tension, our buoyant force, and our weight force.

00:14 So this is it when it's immersed in the water.

00:16 And now, when it's immersed in the oil and the water, it should be oil and water, then we have t, still our weight, fb, and f .a.

00:30 Or f .a is a boiling force due to the oil.

00:34 So the net force on the block is zero in equilibrium.

00:38 So we set f equal to zero, and we get t plus w minus fb is equal to zero.

00:46 So fb is equal to t plus w.

00:49 And that's given in our problem.

00:52 So we plug in our 10 newtons plus our 15 newtons, and we get 25 newtons.

01:02 Question b, oil of density 800 kilograms per meter is added to the beaker.

01:09 What are the directions of these forces? so now, oil forms on all the faces of the box.

01:19 The force is perpendicular to the surface of the block and points towards the surface.

01:30 So the force is going to be perpendicular to each surface and points towards the surface.

01:37 Now, question c asks, what happens to the string tension as the oil is added? so when the oil is added, the block is now submerged into this oil.

01:55 So this adds to a buoyant force, so it makes it bigger.

02:00 So the tension also increases.

02:04 So the oil causes the water to experience more pressure.

02:08 So the tension ultimately increases in the string...

Ace is your personal tutor. It breaks down any question with clear steps so you can learn.

Start Using Ace

Continue solving this problem

Create a free account to:

View full step-by-step solution
Ask follow-up questions with Ace AI
Save progress and study later