Concept explainers
* Helge, Steve, and Heidi are sitting on a sled on a slope covered with a hard snow. The sled is stationary. The friends have different suggestions for how to make the sled start moving. Helge If one of us gets off, the sled will start moving:
Steve: We should invite another person to join us, and then the sled will start moving.
Heidi: We should get off the sled, polish the bottom of the sled to make it smoother and sit back down on it. The sled will then start moving.
Comment on the students' suggestions and decide whose reasoning is correct. Explain using physics concepts, including appropriate diagrams, why those who were incorrect said what they did, and indicate what part of their reasoning was correct.
Want to see the full answer?
Check out a sample textbook solutionChapter 4 Solutions
College Physics: Explore And Apply, Volume 2 (2nd Edition)
Additional Science Textbook Solutions
University Physics with Modern Physics (14th Edition)
University Physics (14th Edition)
The Cosmic Perspective (8th Edition)
Physics: Principles with Applications
The Cosmic Perspective Fundamentals (2nd Edition)
- A box is projected upward onto a ramp that has a 15 degree incline. I know knows that it starts with an initial velocity of 8 m / s. The coefficient of kinetic friction between the box and the ramp is 0.12. Determine the following: a. The distance the box will travel on the ramp. b. The speed of the box when it returns to its original position.arrow_forwardQ6.2 The questions refer to the layout of the figure. There is no friction in the shafts of the pulleys, the cord has negligible mass. The friction between the pulleys and the cord is large enough that the cord does not slide against the pulley. You additionally assume that the pulleys have negligible mass. MI M2 a) Draw a figure with all relevant forces. Draw the direction of movement of the various objects in the system, but not in such a way that they can be confused with the forces. Assume that the block with mass m1 moves downwards. b) What must be the ratio between the masses m1 and m2 for the system to be able to be at rest?arrow_forwardA block is sent up an incline with a velocity of 3.51 m/s. Assume there is no friction between the incline and the block. The angle is at an incline of 31.1 degrees with the horizontal. A) How far up the incline does the block go? B) How long does it take to get there? C) What is it's speed when it gets back to the bottom?arrow_forward
- In a laboratory model of cars skidding to a stop, data are measured for four trials using two blocks. The blocks have identical masses but different coefficients of kinetic friction with a table: k = 0.2 and 0.8. Each block is launched with speed vi = 1 m/s and slides across the level table as the block comes to rest. This process represents the first two trials. For the next two trials, the procedure is repeated but the blocks are launched with speed vi = 2 m/s. Rank the four trials (a) through (d) according to the stopping distance from largest to smallest. If the stopping distance is the same in two cases, give them equal rank. (a) vi = 1 m/s, k = 0.2 (b) vi = 1 m/s, k = 0.8 (c) vi = 2 m/s, k = 0.2 (d) vi = 2 m/s, k = 0.8arrow_forwardThe driver of a speeding truck slams on the brakes and skids to a stop through a distance d. On another trial, the initial speed of the truck is half as large. What now will be the trucks skidding distance? (a) 2d (b) 2d (c) d (d) d/2 (e) d/4arrow_forwardQ5. a) The graph shows the motion of an RC helicopter. What will be the average speed from point ‘A’ to point ‘G’. Between which two points (A-B or E-F) will the speed be more? Calculate.arrow_forward
- The distance from the release point to the target of a curling sheet is around 42.3 meters. A study showed that the coefficient of friction of the surface between the curling stone and ice was .30. How fast should the stone be released to get a bullseye? draw a picturearrow_forwardThe pulley system shown in the figure is used to lift a m= 67-kg crate. Note that one chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to the crate. Assume the masses of the chains, pulleys, and ropes are negligible. Determine the force F required to lift the crate with constant speed. Determine the tension in the upper chain. Determine the tension in the lower chain.arrow_forwardMike pushes a box with a mass of 6.35 kg giving it an initial velocity of 2.35 m/s. The box comes to rest after sliding for 2.39 meters because of the frictional force exerted between the surface and the box. What is the frictional force on the box?arrow_forward
- 2. You pull with a force of 255 N on a rope that is attached to a block of mass 30 kg, and the block slides across the floor at a constant speed of 1.1 m/s. The rope makes an angle of 0 = 40° with the horizontal. Both the force and the velocity of the block are in the xy plane. The block moves only along the direction parallel to the floor. See the figure for a diagram of this situation. a. What is the net force on the block? Explain your b. c. reasoning. Is there friction between the block and the floor? How do you know? Rope 40° 15₂ Draw a Free Body Diagram for the block. Find the magnitude and direction of each force, and express them as vectors.arrow_forwardChoose the correct answer choice. Answer must be in scientific notation with SI units that do not have prefixes except for kg. (m/s NOT cm/s). Answer must be in standard scientific notationarrow_forwardA study found that the coefficient of friction between the ice and curling stone is 0.02. The distance of the curling sheet is around 30 meters. How fast should the stone be to get a bullseye ? draw a picturearrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillPhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning