Learning Materials
Features
Discover
Chapter 8: Q.24 (page 199)
A ball swings in a vertical circle at the end of a -long string. When the ball is at the bottom of the circle, the tension in the string is . What is the speed of the ball at that point?
The speed of the ball at that point is.
Over 30 million students worldwide already upgrade their learning with 91影视!
All the tools & learning materials you need for study success - in one app.
Get started for free
In an old-fashioned amusement park ride, passengers stand inside a 5.0-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers will 鈥渟tick鈥� to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. A sign next to the entrance says 鈥淣o children under 30 kg allowed.鈥� What is the minimum angular speed, in rpm, for which the ride is safe?
is a bird鈥檚-eye view of particles on strings moving in horizontal circles on a tabletop. All are moving at the same speed. Rank in order, from largest to smallest, the tensions . Give your answer in the formand explain your ranking.
As a science fair project, you want to launch an model rocket straight up and hit a horizontally moving target as it passes above the launch point. The rocket engine provides a constant thrust of . The target is approaching at a speed of . At what horizontal distance between the target and the rocket should you launch?
The physics of circular motion sets an upper limit to the speed of human walking. (If you need to go faster, your gait changes from a walk to a run.) If you take a few steps and watch
what鈥檚 happening, you鈥檒l see that your body pivots in circular motion over your forward foot as you bring your rear foot forward for the next step. As you do so, the normal force of the
ground on your foot decreases and your body tries to 鈥渓ift off鈥� from the ground.
a. A person鈥檚 center of mass is very near the hips, at the top of the legs. Model a person as a particle of mass m at the top of a leg of length L. Find an expression for the person鈥檚 maximum walking speed vmax.
b. Evaluate your expression for the maximum walking speed of a 70 kg person with a typical leg length of 70 cm. Give your answer in both m/s and mph, then comment, based on your
experience, as to whether this is a reasonable result. A 鈥渘ormal鈥� walking speed is about 3 mph.
A model rocket is on a cart that is rolling to the right at a speed of . The rocket engine, when it is fired, exerts an vertical thrust on the rocket. Your goal is to have the rocket pass through a small horizontal hoop that is above the ground. At what horizontal distance left of the hoop should you launch?
What do you think about this solution?
We value your feedback to improve our textbook solutions.
Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine