You and your brother argue often about how to safely secure a toddler in a moving car. You insist that special toddler seats are critical in improving the chances of a toddler surviving a crash. Your brother claims that, as long as his wife is buckled in next to him with a seat belt while he drives, she can hold onto their toddler on her lap in a crash. You decide to perform a calculation to try to convince your brother. Consider a hypothetical collision in which the 12-kg toddler and his parents are riding in a car traveling at 60 mi/h relative to the ground. The car strikes a wall, tree, or another car, and is brought to rest in 0.10 s. You wish to demonstrate to your brother the magnitude of the force necessary for his wife to hold onto their child during the collision.
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Chapter 9 Solutions
EBK PHYSICS FOR SCIENTISTS AND ENGINEER
- You and your brother argue often about how to safely secure a toddler in a moving car. You insist that special toddler seats are critical in improving the chances of a toddler surviving a crash. Your brother claims that, as long as his wife is buckled in next to him with a seat belt while he drives, she can hold onto their toddler on her lap in a crash. You decide to perform a calculation to try to convince your brother. Consider a hypothetical collision in which the 14 kg toddler and his parents are riding in a car traveling at 47 mi/h relative to the ground. The car strikes a wall, tree, or another car, and is brought to rest in 0.13 s. You wish to demonstrate to your brother the magnitude of the force necessary for his wife to hold onto their child during the collision. What is the magnitude of this force (in N)? ______________Narrow_forwardA 2.50 kg box sits halfway up a 16.0 m long ramp that is inclined at an angle of 16.00. You shove a second box, of mass 1.50 kg, that's at the bottom of the ramp, so that it starts sliding up the ramp with a speed of 20.0 m/s. It hits the first box, sticks to it, and they both continue to slide up the ramp. The coefficient of kinetic friction between the boxes and the ramp is 0.200. Where, from the bottom of the ramp, do they come to rest?arrow_forwardAt a time when mining asteroids has become feasible, astronauts have connected a line between their 3070-kg space tug and a 5580-kg asteroid. They pull on the asteroid with a force of 307 N. Initially the tug and the asteroid are at rest, 436 m apart. How much time does it take for the ship and the asteroid to meet?arrow_forward
- intro to physics, thank you! You set up a 20 cm tall ramp on a 75 cm tall table. The ramp is inclined at 30° to the horizontal.You place a 500 g block at the end of the ramp, and release a 750 g block from rest at the topof the ramp. The ramp exerts 1.6 N of friction on the block. The two blocks are equippedwith velcro so they stick together after colliding. The ramp is designed so the objects travelhorizontally off the table immediately after colliding.(a) How fast are the two blocks traveling just after the collision?(b) How far from the table do they land?arrow_forwardNewton's Cradle is a physics toy with several balls hanging from a string in contact with one another. Raise a ball up on one end and after it taps the others a single ball flies off the far end while the first ball comes to rest. There's a cat playing with one on our class website who can teach you the answer to this question. Consider one that has five balls initially at rest. What happens if you raise two balls together off the left side, and then let go so together they hit the stack of remaining three stationary balls? a. Three come up on the right, leaving two at rest in the center. b. Two balls come up on the right, leaving three at rest in the center. c. They meet and stop. d. One comes up on the right, leaving four at rest in the center.arrow_forwardA 79.5kg person, running horizontally with a velocity of +2.34m/s,jumps onto a 11.8kg sled that is initially at rest. a)Ignoring the effects of friction during the collision, find the velocity of the sled and person as they move away. b) The sled and person coast 30.0m on level snow before coming to rest. What is the coefficient of kinetic friction between the sled and the snow? Note: the tolerance is positive negative 1 in the 3rd significant digit (a) Number i (b) Number i Units Unitsarrow_forward
- A meter stick has a mass of 0.5 kg and a center of mass at the 50 cm mark. Using two fingers, one at the 10 cm mark and the other at the 40 cm mark, you hold the meter stick in a stationary horizontal position. Find the forces that your fingers put on the meter stick.arrow_forwardAnswer 1 and 2 please 1. Suppose you are in an enclosed boxcar, initially at rest on a track with no friction. You throw heavy darts at the front wall of the car which stick right into it. You MAY IGNORE DRAG FRICTION of the darts while they are in the air. Describe the motion of the cart. Select one: i) The cart does not move. ii) The cart moves backwards while the darts are in the air and stops completely when the dart impacts the front wall. iii) The cart moves backwards while the dart is in the air and slows down a bit but is still going backward slowly after the dart’s impact. iv) The cart moves forward slowly. v) The cart moves backwards while the dart is in the air and moves forwards slowly after impact. 2. Suppose you are in an enclosed boxcar, initially at rest on a track with no friction. You throw heavy darts at the front wall of the car which stick right into it. You MAY NOT IGNORE DRAG FRICTION of the darts while they are in the air. Describe the motion of the cart.…arrow_forwardMy sister Crystal of mass M1= 50 kg is on an ice-covered sidewalk with her dog Buster, who has mass M2= 38 kg. They are initially a distanced= 5.0 m apart.By pulling on the massless leash, my sister exerts a constant force F= 30.0 N on Buster; Buster slides towards her. How fast is Buster moving when he and my sister meet? (The leash is not rigid, so the distance can change between them. They also end up at the same point, which means even if you can’t solve for their position,you can set them equal to one another.)arrow_forward
- 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 vi = 0. The dog then runs on top of the raft at vd = vd with respect to the water (see figure B below). The dog has one sixth 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.) vr =arrow_forwardAn unfortunate astronaut loses his grip during a spacewalk and finds himself floating away from the space station, carrying only a rope and a bag of tools. First he tries to throw a rope to his fellow astronaut, but the rope is too short. In a last ditch effort, the astronaut throws his bag of tools in the direction of his motion, away from the space station. The astronaut has a mass of ?a=102 kg and the bag of tools has a mass of ?b=10.0 kg. If the astronaut is moving away from the space station at ?i=1.50 m/s initially, what is the minimum final speed ?b,f of the bag of tools with respect to the space station that will keep the astronaut from drifting away forever? ?b,f = ? m/sarrow_forwardYou have been called to testify as an expert witness in a trial involving a head-on collision. Car A weighs 15151515 lb and was traveling eastward. Car B weighs 11251125 lb and was traveling westward at 41.041.0 mph. The cars locked bumpers and slid eastward with their wheels locked for 18.518.5 ft before stopping. You have measured the coefficient of kinetic friction between the tires and the pavement to be 0.7500.750. How fast (in miles per hour) was car A traveling just before the collision? (This problem uses English units because they would be used in a U.S. legal proceeding.)arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning