Usually, we do not walk or even stand on a lightweight boat or raft because of the danger of falling into the water. If you have ever stepped off a small boat onto a dock, however, you have probably noticed that the boat moves away from the dock as you step toward the dock or out of the boat. A heavy dog running on a long lightweight raft presents a similar situation. At first, the raft and the dog are at rest with respect to the water (see figure A below) so that ✓; = 0. The dog then runs on top of the raft at ✓d = v₁₁ with respect to the water (see figure B below). The dog has one fourth the mass of the raft. Find an expression for the velocity of the raft after the dog began running. (Use the following as necessary: Vd.) V A. √₁ = ? B. V₁ = 0

Usually, we do not walk or even stand on a lightweight boat or raft because of the danger of falling into the water. If you have ever stepped off a small boat onto a dock, however, you have probably noticed that the boat moves away from the dock as you step toward the dock or out of the boat. A heavy dog running on a long lightweight raft presents a similar situation. At first, the raft and the dog are at rest with respect to the water (see figure A below) so that ✓; = 0. The dog then runs on top of the raft at ✓d = v₁₁ with respect to the water (see figure B below). The dog has one fourth the mass of the raft. Find an expression for the velocity of the raft after the dog began running. (Use the following as necessary: Vd.) V A. √₁ = ? B. V₁ = 0

Physics for Scientists and Engineers, Technology Update (No access codes included)

9th Edition

ISBN:9781305116399

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter5: The Laws Of Motion

Section: Chapter Questions

Problem 5.20CQ: Balancing carefully, three boys inch out onto a horizontal tree branch above a pond, each planning...

See similar textbooks

Similar questions

Let us make the (unrealistic) assumption that a boat of mass m gliding with initial velocity v0 in water is slowed by a viscous retarding force of magnitude bv2, where b is a constant, (a) Find and sketch v(t). How long does it take the boat to reach a speed of v0/l000? (b) Find x(t). How far does the boat travel in this time? Let m = 200 kg, v0 = 2 m/s, and b = 0.2 Nm-2s2.
The United States possesses the ten largest warships in the world, aircraft carriers of the Nimitz class. Suppose one of the ships bobs up to float 11.0 cm higher in the ocean water when 50 fighters take off from it in a time interval of 25 min, at a location where the free-fall acceleration is 9.78 m/s2. The planes have an average laden mass of 29 000 kg. Find the horizontal area enclosed by the waterline of the ship.
A large crate of mass m is placed on the flatbed of a truck but not tied down. As the truck accelerates forward with acceleration a, the crate remains at rest relative to the truck. What force causes the crate to accelerate? (a) the normal force (b) the gravitational force (c) the friction force (d) the ma force exerted by the crate (e) No force is required.
A black widow spider hangs motionless from a web that extends vertically from the ceiling above. If the spider has a mass of 1.5 g, what is the tension in the web?
An aluminum block of mass m1 = 2.00 kg and a copper block of mass m2 = 6.00 kg are connected by a light string over a frictionless pulley. They sit on a steel surface as shown in Figure P5.46, where = 30.0. (a) When they are released from rest, will they start to move? If they do, determine (b) their acceleration and (c) the tension in the string. If they do not move, determine (d) the sum of the magnitudes of the forces of friction acting on the blocks. Figure P5.46
The starship Enterprise has its tractor beam locked onto some valuable debris and is trying to pull it toward the ship. A Klingon battle cruiser and a Romulan warbird are also trying to recover the item by pulling the debris with their tractor beams as shown in Figure P5.25. a. Given the following magnitudes of the tractor beam forces, find the net force experienced by the debris: FEnt = 7.59 106 N, FRom = 2.53 106 N, and FKling = 8.97 105 N. b. If the debris has a mass of 2549 kg, what is the net acceleration of the debris? FIGURE P5.25
Does the ground need to exert a force on you for you to jump off the ground, or do you need to exert a force on the ground? If the ground must exert a force on you, is that force greater than the force you exert on the ground?
To lift off from the Moon, a 9.50 105 kg rocket needs a thrust larger than the force of gravity. If the exhaust velocity is 4.25 103 m/s, at what rate does the exhaust need to be expelled to provide sufficient thrust? The acceleration due to gravity on the Moon is 1.62 m/s2.
The x and y coordinates of a 4.00-kg particle moving in the xy plane under the influence of a net force F are given by x = t4 6t and y = 4t2 + 1, with x and y in meters and t in seconds. What is the magnitude of the force F at t = 4.00 s?
How much fuel would be needed for a 1000-kg rocket (this is its mass with no fuel) to take off from Earth and reach 1000 m/s in 30 s? The exhaust speed is 1000 m/s.
A 75.0-g arrow, fired at a speed of 110 m/s to the left, impacts a tree, which it penetrates to a depth of 12.5 cm before coming to a stop. Assuming the force of friction exerted by the tree is constant, what are the magnitude and direction of the friction force acting on the arrow?
An astronaut out on a spacewalk to construct a new section of the International Space Station walks with a constant velocity of 2.00 m/s on a flat sheet of metal placed on a flat, frictionless, horizontal honeycomb surface linking the two parts of the station. The mass of the astronaut is 75.0 kg, and the mass of the sheet of metal is 245 kg. a. What is the velocity of the metal sheet relative to the honeycomb surface? b. What is the speed of the astronaut relative to the honeycomb surface?