Concept explainers
In which of the following situations is there zero net force on the body? (i) An airplane flying due north at a steady 120 m/s and at a constant altitude; (ii) a car driving straight up a hill with a 3° slope at a constant 90 km/h; (iii) a hawk circling at a constant 20 km/h at a constant height of 15 m above an open field; (iv) a box with slick, frictionless surfaces in the back of a truck as the truck accelerates forward on a level road at 5 m/s2.
Learn your wayIncludes step-by-step video
Chapter 4 Solutions
University Physics with Modern Physics (14th Edition)
Additional Science Textbook Solutions
Life in the Universe (4th Edition)
College Physics (10th Edition)
College Physics
An Introduction to Thermal Physics
The Cosmic Perspective Fundamentals (2nd Edition)
Lecture- Tutorials for Introductory Astronomy
- A dog and a sledge are on the frictionless ice of a frozen lake, 14.4 m apart but connected by a rope of negligible mass. The dog exerts a certain horizontal force (N) on the rope. If magnitudes of the sledge and the dog accelerations are 0.5 m/s² and 0.1 m/s?, respectively. How far from the dog's initial position (m) do they meet?arrow_forwarda person of mass 65 kg is ascending on an escalator at a constant velocity of 2.5 m/s [22° above the horizontal]. The magnitude of the net force acting on the person is ?arrow_forward•7SSMThere are two forces on the 2.00 kg box in the overhead view of Fig. 5-31, but only one is shown. For F1 = 20.0 N, a = 12.0 m/s2, and θ = 30.0°, find the second force (a) in unit-vector notation and as (b) a magnitude and (c) an angle relative to the positive direction of the x axis.arrow_forward
- A force of 32 N, parallel to the inclined plane, is necessary to make a crate rise, with constant speed, on an inclined plane,without frictiin, which makes an angle of 30° with the horizontal. The mass of the crate is. a) 160 kg b) 6,5 kg c) 3,8 kg d) 3,3 kg e) 5,7 kgarrow_forwardYou are a member of an alpine rescue team and must get a box of supplies, with mass 2.30 kg , up an incline of constant slope angle 30.0 ∘ so that it reaches a stranded skier who is a vertical distance 2.50 m above the bottom of the incline. There is some friction present; the kinetic coefficient of friction is 6.00×10−2. Since you can't walk up the incline, you give the box a push that gives it an initial velocity; then the box slides up the incline, slowing down under the forces of friction and gravity. Take acceleration due to gravity to be 9.81 m/s2. Use the work-energy theorem to calculate the minimum speed v that you must give the box at the bottom of the incline so that it will reach the skier. Express your answer numerically, in meters per second.arrow_forwardAn elevator, which weighs 8 tons with its load, is descending with a speed of 900 ft/min. Ifthe load on the cables must not exceed 14 tons, what is the shortest distance in which the elevator can be stopped?arrow_forward
- Tarzan, who weighs 820 N, swings from a cliff at the end of a 20.0 m vine that hangs from a high tree limb and initially makes an angle of 22.0 with the vertical. Assume that an x axis extends horizontally away from the cliff edge and a y axis extends upward. Immediately after Tarzan steps off the cliff, the tension in the vine is 760 N. Just then, what are (a) the force on him from the vine in unit-vector notation and the net force on him (b) in unit-vector notation and as (c) a magnitude and (d) an angle relative to the positive direction of the x axis? What are the (e) magnitude and (f) angle of Tarzan’s acceleration just then?arrow_forwardCalculate the magnitude of the normal force on a 15.0-kg block in the following circumstances: (a) The block is resting on a level surface. (b) The block is resting on a surface tilted up at a 30.0° angle with respect to the horizontal. (c) The block is resting on the floor of an elevator that is accelerating upwards at 3.00 m/s2. (d) The block is on a level surface and aforce of 125 N is exerted on it at an angle of 30.0° above the horizontal.arrow_forwardYou are a member of an alpine rescue team and must get a box of supplies, with mass 2.20 kg , up an incline of constant slope angle 30.0 so that it reaches a stranded skier who is a vertical distance 3.10 m above the bottom of the incline. There is some friction present; the kinetic coefficient of friction is 6.00×10−2. Since you can't walk up the incline, you give the box a push that gives it an initial velocity; then the box slides up the incline, slowing down under the forces of friction and gravity. Take acceleration due to gravity to be 9.81 m/s2 . Use the work-energy theorem to calculate the minimum speed v that you must give the box at the bottom of the incline so that it will reach the skier. Express your answer numerically, in meters per second.arrow_forward
- the coefficient of static friction between block A and a horizontal floor is 0.320, and the coefficient of static friction between block B and the floor is 0.300. The mass of each block is 2.00kg,and they are connected together by a cord. If a horizontal force F pulling on block B is slowly increased ,in a direction parallel to the connectin cord,until the block start sliding ,what is the magnitude of F at the instant that they start to slide?arrow_forwardThe parachute on a race car of weight 8 820 N opens at theend of a quarter-mile run when the car is traveling at 35.0 m/s.What total retarding force must be supplied by the parachuteto stop the car in a distance of 1.00 x 103 m?arrow_forwardA skier with mass of 55 kg (including winter clothes and ski equipment), slides straight down a smooth slope (not unlike a flat inclined plane) that makes an angle of 50° with the horizontal. A skier with mass of 55 kg (including winter clothes and ski equipment), slides straight down a smooth slope (not unlike a flat inclined plane) that makes an angle of 50° with the horizontal. What is the force of friction between the skies and the snow? given uk=0.19arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning