![Physics for Scientists and Engineers, Technology Update (No access codes included)](https://www.bartleby.com/isbn_cover_images/9781305116399/9781305116399_largeCoverImage.gif)
Concept explainers
A 9.00-kg object starting from rest falls through a viscous medium and experiences a resistive force given by Equation 6.2. The object reaches one half its terminal speed in 5.54 s. (a) Determine the terminal speed. (b) At what time is the speed of the object three-fourths the terminal speed? (c) How far has the object traveled in the first 5.54 s of motion?
(a)
![Check Mark](/static/check-mark.png)
The terminal speed of the object.
Answer to Problem 6.65CP
The terminal speed of the object is
Explanation of Solution
The mass of the object is
Write the expression for the terminal speed of the object
Here,
Write the expression for the speed of the object at an instant of time
Here,
From the given condition, it is clear that the speed of the object is one half of its terminal speed at
Substitute
Further solve the above expression.
Substitute
Conclusion:
Substitute
Therefore, the terminal speed of the object is
(b)
![Check Mark](/static/check-mark.png)
The time at which the speed of the object is three-fourth of the terminal speed.
Answer to Problem 6.65CP
The time at which the speed of the object is three-fourth of the terminal speed is
Explanation of Solution
From the given condition, it is clear that the speed of the object is three-fourth of its terminal speed.
Substitute
Rearrange the above expression for
Conclusion:
Substitute
Therefore, the time at which the speed of the object is three-fourth of the terminal speed is
(c)
![Check Mark](/static/check-mark.png)
The distance travelled by the object in first
Answer to Problem 6.65CP
The distance travelled by the object in first
Explanation of Solution
Write the expression for the speed of an object
Here,
Rearrange the above expression for
Recall equation (II)
Substitute
Conclusion:
Substitute
Therefore, the distance travelled by the object in first
Want to see more full solutions like this?
Chapter 6 Solutions
Physics for Scientists and Engineers, Technology Update (No access codes included)
- An elevator filled with passengers has a total mass of 1960 kg and is suspended from a single cable. The elevator rises to the top floor in the following three stages of motion: First, starting from rest on the ground floor, it accelerates upward at 0.81 m/s2 for 1.85 s. Next, it travels at constant speed for 5.03 s. Finally, is slows with an acceleration of magnitude 0.34 m/s2 until it comes to rest at the top floor. Assume the only two forces on the elevator are the tension in the cable and gravity. What is the distance, in meters, from the ground floor to the top floor?arrow_forwardA 2 kg box is against a vertical wall by a small force (f1=10n) perpendicular to the surface of the wall, and pushed upward by a force. Force applied to the box vertically. The force pushes the box and the wall. Determine the value of the applied force to keep the box moving upward at a constant velocityarrow_forwardA crate of mass 55.6kg is being transported on the flatbed of a pickup truck. The coefficient of static friction between the crate and the trucks flatbed is 0.330, and the coefficient of kinetic friction is 0.320. The truck barely exceeds this acceleration and then moves with constant acceleration, with the crate sliding along its bed. What is the acceleration of the crate relative to the ground?arrow_forward
- A skier starts from rest and slides 9m down a slope. In what time after starting from rest will the skier acquire a velocity of 24 m/s? Assume constant acceleration and friction is negligible. While driving down the road, a firefly strikes the windshield of a bus and makes a quite obvious mess in front of the face of the driver. This is a clear case of Newton’s third law of motion. The firefly hit the bus and the bus hits the firefly. Which of the two forces is greater: the force on the firefly or the force on the bus?arrow_forwardAn object at rest falls from a height of 65.0 m. It attains its terminal velocity after it had traveled 25.0 m. Neglecting air resistance, its terminal velocity is found to be 75 percent of its supposed velocity just before it hits the ground. (a) Find the terminal velocity of the body. (b) How long does it take, after reaching its terminal velocity, to reach the ground? Assume Newton's law of resistance holds.arrow_forwardYou are pushing a wooden crate against a rubber floor. The two surfaces have a static coefficient of friction of 0.45 and a kinetic coefficient of friction of 0.38. The floor is horizontal, and the crate has a mass of 25.0 kg, and is initially at rest. You are pushing with a horizontal force of 155 N. What is the magnitude of the force of friction in this case? Give your answer in units of N, to three significant figures.arrow_forward
- A small piece of Styrofoam packing material is dropped from a height of 2.10 m above the ground. Until it reaches terminal speed, the magnitude of its acceleration is given by a = g - Bv. After falling 0.400 m, the Styrofoam effectively reaches terminal speed, and then takes 4.70 s more to reach the ground. (a) What is the value of the constant B? (b) What is the acceleration at t = 0? m/s² (down) (c) What is the acceleration when the speed is 0.150 m/s? m/s² (down)arrow_forwardYou are designing a high-speed elevator for a new skyscraper. The elevator will have a mass limit of 2400 kg (including passangers). For passenger comfort, you choose the maximum ascent speed to be 18.0 m/s, the maximum descent speed to be 10.0 m/s, and the maximum acceleration magnitude to be 3.20 m/s^2. Ignore friction. What is the maximum upward force that the supporting cables exert on the elevator car? What is the minimum upward force that the supporting cables exert on the elevator car? What is the minimum time it will take the elevator to ascend from the lobby to the observation deck, a vertical displacement of 640 m? What is the maximum value of a 60.0 kg passanger's apparent weight during the ascent? What is the minimum value of 60.0 kg passenger's apparent weight during the ascent? What is the minimum time it will take the elevator to descend to the lobby from the observation deck, a vertical displacement of 640 m?arrow_forwardA 2540 kg test rocket is launched vertically from the launch pad. Its fuel (of negligible mass) provides a thrust force such that its vertical velocity as a function of time is given by v(t) = At + Bt2, where A and B are constants and time is measured from the instant the fuel is ignited. The rocket has an upward acceleration of 1.50 m/s2 at the instant of ignition and, 1.00 s later, an upward velocity of 2.00 m/s. (a) Determine A and B, including their SI units. (b) At 4.00 s after fuel ignition, what is the acceleration of the rocket, and (c) what thrust force does the burning fuel exert on it, assuming no air resistance? Express the thrust in newtons and as a multiple of the rocket’s weight. (d) What was the initial thrust due to the fuel?arrow_forward
- The 1.0 kg block in the figure is tied to the wall with a rope. It sits on top of the 2.0 kg block. The lower block is pulled to the right with a tension force of 20 N. The coefficient of kinetic friction at both the lower and upper surfaces of the 2.0 kg block is μkμk = 0.42. What is the acceleration of the 2.0 kg block? Express your answer with the appropriate units. The anwer is NOT 3.826 1.6 3.7 7.942arrow_forwardA 3.45×103 kg train is stopped at a station. The train must go around a 149 m diameter corner right after it leaves the station. As the train leaves the station it provides a constant forward force of 1.67×103 N. What is the train's acceleration after 5.00 s?arrow_forwardAn elevator cab is pulled upward by a cable. The cab and its single occupant have a combined mass of 2030 kg. When that occupant drops a coin, its acceleration relative to the cab is 7.90 m/s2 downward. What is the tension in the cable?arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningClassical Dynamics of Particles and SystemsPhysicsISBN:9780534408961Author:Stephen T. Thornton, Jerry B. MarionPublisher:Cengage Learning
![Text book image](https://www.bartleby.com/isbn_cover_images/9781133104261/9781133104261_smallCoverImage.gif)
![Text book image](https://www.bartleby.com/isbn_cover_images/9780534408961/9780534408961_smallCoverImage.gif)