
Concept explainers
(a)
The magnitude of static frictional force exerted by road on each tire.
(a)

Answer to Problem 129P
The magnitude of static frictional force exerted by road on each tire is
Explanation of Solution
Consider Newton’s second law to find the force exerted by road on bicycle, since it is the only external force acting on bicycle.
Write the Mathematical expression for Newton’s second law
Here,
Both wheels of bicycle experience external force between road and wheel. Hence the expression for that force in terms of velocity is
Here,
Therefore, the expression of frictional force is
Conclusion:
Substitute,
Therefore, the magnitude of static frictional force exerted by road on each tire is
(b)
The
(b)

Answer to Problem 129P
The angular acceleration of two wheels is
Explanation of Solution
Write the expression for angular speed
Here,
Write the expression for angular acceleration
Here,
Conclusion:
Substitute,
Substitute
Therefore, the angular acceleration of two wheels is
(c)
The net torque acting on wheel.
(c)

Answer to Problem 129P
The net torque acting on wheel is
Explanation of Solution
Write the expression for net torque
Here,
Write the expression for moment of inertia
Here,
Substitute equation (VII) in (VI)
Conclusion:
Substitute,
Therefore, the net torque acting on wheel is
(d)
The normal force applied to a wheel by each of the brake pads.
(d)

Answer to Problem 129P
The normal force applied to a wheel by each of the brake pads is
Explanation of Solution
There are two components of net torque acting on each wheel, one is static friction force acting between road and wheel, and the other is the kinetic friction force acting on brake pads.
The direction of both forces will be opposite to each other. If the bicycle turns to right, static friction force will be in clockwise direction, and kinetic friction will be in counter clockwise direction.
Write the expression for net force in terms components
Rearrange equation (IX) to obtain expression for
Write the expression for normal force
Conclusion:
Substitute,
Substitute
Therefore, the normal force applied to a wheel by each of the brake pads is
Want to see more full solutions like this?
Chapter 8 Solutions
Physics
- 6. A car drives at steady speed around a perfectly circular track. (a) The car's acceleration is zero. (b) The net force on the car is zero. (c) Both the acceleration and net force on the car point outward. (d) Both the acceleration and net force on the car point inward. (e) If there is no friction, the acceleration is outward.arrow_forward9. A spring has a force constant of 100 N/m and an unstretched length of 0.07 m. One end is attached to a post that is free to rotate in the center of a smooth. table, as shown in the top view in the figure below. The other end is attached to a 1kg disc moving in uniform circular motion on the table, which stretches the spring by 0.03 m. Friction is negligible. What is the centripetal force on the disc? Top View (a) 0.3 N (b) 3.0 N (c) 10 N (d) 300 N (e) 1000 Narrow_forward4. A child has a ball on the end of a cord, and whirls the ball in a vertical circle. Assuming the speed of the ball is constant (an approximation), when would the tension in the cord be greatest? (a) At the top of the circle. (b) At the bottom of the circle. (c) A little after the bottom of the circle when the ball is climbing. (d) A little before the bottom of the circle when the ball is descending quickly. (e) Nowhere; the cord is pulled the same amount at all points.arrow_forward
- 3. In a rotating vertical cylinder (Rotor-ride) a rider finds herself pressed with her back to the rotating wall. Which is the correct free-body diagram for her? (a) (b) (c) (d) (e)arrow_forward8. A roller coaster rounds the bottom of a circular loop at a nearly constant speed. At this point the net force on the coaster cart is (a) zero. (b) directed upward. (c) directed downward. (d) Cannot tell without knowing the exact speed.arrow_forward5. While driving fast around a sharp right turn, you find yourself pressing against the left car door. What is happening? (a) Centrifugal force is pushing you into the door. (b) The door is exerting a rightward force on you. (c) Both of the above. (d) Neither of the above.arrow_forward
- 7. You are flung sideways when your car travels around a sharp curve because (a) you tend to continue moving in a straight line. (b) there is a centrifugal force acting on you. (c) the car exerts an outward force on you. (d) of gravity.arrow_forward1. A 50-N crate sits on a horizontal floor where the coefficient of static friction between the crate and the floor is 0.50. A 20-N force is applied to the crate acting to the right. What is the resulting static friction force acting on the crate? (a) 20 N to the right. (b) 20 N to the left. (c) 25 N to the right. (d) 25 N to the left. (e) None of the above; the crate starts to move.arrow_forward3. The problem that shall not be named. m A (a) A block of mass m = 1 kg, sits on an incline that has an angle 0. Find the coefficient of static friction by analyzing the system at imminent motion. (hint: static friction will equal the maximum value) (b) A block of mass m = 1kg made of a different material, slides down an incline that has an angle 0 = 45 degrees. If the coefficient of kinetic friction increases is μ = 0.5 what is the acceleration of the block? karrow_forward
- 2. Which of the following point towards the center of the circle in uniform circular motion? (a) Acceleration. (b) Velocity, acceleration, net force. (c) Velocity, acceleration. (d) Velocity, net force. (e) Acceleration, net force.arrow_forwardProblem 1. (20 pts) The third and fourth stages of a rocket are coastin in space with a velocity of 18 000 km/h when a smal explosive charge between the stages separate them. Immediately after separation the fourth stag has increased its velocity to v4 = 18 060 km/h. Wha is the corresponding velocity v3 of the third stage At separation the third and fourth stages hav masses of 400 and 200 kg, respectively. 3rd stage 4th stagearrow_forwardMany experts giving wrong answer of this question. please attempt when you 100% sure . Otherwise i will give unhelpful.arrow_forward
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningUniversity Physics (14th Edition)PhysicsISBN:9780133969290Author:Hugh D. Young, Roger A. FreedmanPublisher:PEARSONIntroduction To Quantum MechanicsPhysicsISBN:9781107189638Author:Griffiths, David J., Schroeter, Darrell F.Publisher:Cambridge University Press
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningLecture- Tutorials for Introductory AstronomyPhysicsISBN:9780321820464Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina BrissendenPublisher:Addison-WesleyCollege Physics: A Strategic Approach (4th Editio...PhysicsISBN:9780134609034Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart FieldPublisher:PEARSON





