/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 41 A motorcycle has a constant spee... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

A motorcycle has a constant speed of \(25.0 \mathrm{m} / \mathrm{s}\) as it passes over the top of a hill whose radius of curvature is \(126 \mathrm{m}\). The mass of the motorcycle and driver is 342 kg. Find the magnitudes of (a) the centripetal force and (b) the normal force that acts on the cycle.

Short Answer

Expert verified
(a) 1696.43 N; (b) 1655.17 N.

Step by step solution

01

Understanding the Problem

We need to determine the centripetal force and the normal force acting on a motorcycle with a mass of 342 kg traveling at a constant speed of \(25.0 \text{ m/s}\) over the top of a hill with a curvature radius of \(126 \text{ m}\).
02

Calculating the Centripetal Force

To find the centripetal force \(F_c\), we use the formula \(F_c = \frac{mv^2}{r}\), where \(m\) is the mass, \(v\) is the velocity, and \(r\) is the radius of curvature.\[ F_c = \frac{342 \times (25.0)^2}{126} \]Calculate to get:\[ F_c = \frac{342 \times 625}{126} = \frac{213750}{126} \approx 1696.43 \text{ N} \]
03

Calculating the Normal Force

The normal force \(N\) can be calculated considering the forces acting on the motorcycle at the top of the hill. At this point, the gravitational force \(mg\) and centripetal force \(F_c\) combine such that:\[ N + F_c = mg \]Thus, the normal force is:\[ N = mg - F_c \]Substitute the known values:\[ N = 342 \times 9.8 - 1696.43 \approx 3351.6 - 1696.43 = 1655.17 \text{ N} \]
04

Assigning Units and Determining Precision

Both the centripetal force and normal force are measured in newtons (N). Ensure that our final answers are presented to two decimal places as shown, confirming the precision of our calculations.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Normal Force
The normal force is an essential concept in physics that describes the support force exerted by a surface, such as a road, on an object, preventing it from falling through. In the context of our motorcycle problem, the normal force acts perpendicular to the surface of the hill at the peak of the curve. Here, the motorcycle's weight and the necessary centripetal force combine to influence the normal force's magnitude.

To calculate the normal force at the top of the hill, where forces acting are slightly different from the flat or upward sloping surfaces, it's crucial to apply the following formula:
  • The gravitational force acting on the motorcycle: \( mg = 342 \times 9.8 = 3351.6 \ ext{ N} \)
  • Subtract the centripetal force from the gravitational force, resulting in the formula:\[ N = mg - F_c \]
  • Applying our values gives us \[ N = 3351.6 - 1696.43 \approx 1655.17 \ ext{ N} \]
In summary, the normal force on a curved path like a hilltop is reduced compared to a flat surface because part of the gravitational force contributes to maintaining circular motion.
Curvature Radius
The curvature radius is a crucial factor in understanding the motion of objects along curved paths. It influences the type of motion and the forces experienced. In our case, the motorcycle passes over a hilltop with a curvature radius of 126 meters.

The curvature radius determines how sharply a path curves. A smaller radius means a sharper turn. For a motorcycle, the radius of curvature influences how much centripetal force is required to maintain the path over the curve.
For our specific scenario:
  • The centripetal force needed to sustain the motorcycle's motion along a curve is given by: \[ F_c = rac{mv^2}{r} \]
  • The radius of curvature (\( r = 126 \) m in this case) is used in this formula to calculate the required centripetal force.
  • The sharper the turn (smaller \( r \)), the greater the required centripetal force for the same speed. Conversely, a larger \( r \) means less force is needed.
By understanding the curvature radius, engineers can design safer road networks and vehicles that can handle the resulting forces efficiently.
Motorcycle Mechanics
Motorcycle mechanics, particularly in dealing with curved paths, play a vital role in ensuring rider stability and safety. When a motorcycle travels over a hill, several forces come into play, including gravity, normal force, and centripetal force.

Key factors in motorcycle dynamics on curves include:
  • Centripetal force: This inward force is crucial for maintaining the curved motion as the motorcycle changes direction over a hilltop.
  • Normal force: The force exerted perpendicular to the surface, varying as the motorcycle ascends or descends.
  • Gravity: The force pulling the motorcycle downward, which competes with the normal force at the hill’s summit.

Fueling these interactions are the design choices in suspension systems, tires, and the rider’s ability to shift weight accordingly. Understanding how these elements work harmoniously allows for better control and safety on winding roads.
Forces in Physics
Forces are fundamental to understanding how objects move and interact in the physical world. In physics, forces describe interactions between objects that can change an object's speed, direction, or shape.

In our motorcycle scenario, several forces work together:
  • Gravitational Force (Weight): This is the force due to gravity acting downwards on the motorcycle, which is calculated as \( mg \).
  • Normal Force: Reacts perpendicular to the surface, balancing part of the gravitational pull.
  • Centripetal Force: Necessary for changing direction and maintaining circular motion through the hill's curvature.
To solve real-world problems, understanding how these forces interplay is essential. For instance, on a hilltop, the normal force decreases as the gravitational force aids the centripetal requirement of motion, showcasing a practical application of these principles. Ultimately, a grasp of physics forces allows us to predict and optimize object interactions within their environments.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

How long does it take a plane, traveling at a constant speed of \(110 \mathrm{m} / \mathrm{s},\) to fly once around a circle whose radius is \(2850 \mathrm{m} ?\)

A special electronic sensor is embedded in the seat of a car that takes riders around a circular loop-the-loop ride at an amusement park. The sensor measures the magnitude of the normal force that the seat exerts on a rider. The loop- the-loop ride is in the vertical plane and its radius is \(21 \mathrm{m}\). Sitting on the seat before the ride starts, a rider is level and stationary, and the electronic sensor reads \(770 \mathrm{N}\). At the top of the loop, the rider is upside down and moving, and the sensor reads \(350 \mathrm{N}\). What is the speed of the rider at the top of the loop?

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be \(43.3 \mathrm{km} / \mathrm{s}\) and \(58.6 \mathrm{km} / \mathrm{s} .\) The slower planet's orbital period is 7.60 years. (a) What is the mass of the star? (b) What is the orbital period of the faster planet, in years?

A Dangerous Ride. You and your exploration team are stuck on a steep slope in the Andes Mountains in Argentina. A deadly winter storm is approaching and you must get down the mountain before the storm hits. Your path leads you around an extremely slippery, horizontal curve with a diameter of \(90 \mathrm{m}\) and banked at an angle of \(40.0^{\circ}\) relative to the horizontal. You get the idea to unpack the toboggan that you have been using to haul supplies, load your team upon it, and ride it down the mountain to get enough speed to get around the banked curve. You must be extremely careful, however, not to slide down the bank: At the bottom of the curve is a steep cliff. (a) Neglecting friction and air resistance, what must be the speed of your toboggan in order to get around the curve without sliding up or down its bank? Express your answer in \(\mathrm{m} / \mathrm{s}\) and \(\mathrm{m} .\) p.h. (b) You will need to climb up the mountain and ride the toboggan down in order to attain the speed you need to safely navigate the curve (from part (a)), The mountain slope leading into the curve is at an angle of \(30.0^{\circ}\) relative to the horizontal, and the coefficient of kinetic friction between the toboggan and the surface of the slope is \(\left(\mu_{\text {mrantain }}=0.15\right) .\) How far up the mountain (distance along the slope, not elevation) from the curve should you start your ride? Note: the path down the mountain levels off at the bottom so that the toboggan enters the curve moving in the horizontal plane (i.e., in the same plane as the curve).

Pilots of high-performance fighter planes can be subjected to large centripetal accelerations during high-speed turns. Because of these accelerations, the pilots are subjected to forces that can be much greater than their body weight, leading to an accumulation of blood in the abdomen and legs. As a result, the brain becomes starved for blood, and the pilot can lose consciousness ( "black out"). The pilots wear "anti-G suits" to help keep the blood from draining out of the brain. To appreciate the forces that a fighter pilot must endure, consider the magnitude \(F_{\mathrm{N}}\) of the normal force that the pilot's seat exerts on him at the bottom of a dive. The magnitude of the pilot's weight is \(W\). The plane is traveling at \(230 \mathrm{m} / \mathrm{s}\) on a vertical circle of radius \(690 \mathrm{m} .\) Determine the ratio \(F_{\mathrm{N}} / W .\) For comparison, note that blackout can occur for values of \(F_{\mathrm{N}} / W\) as small as 2 if the pilot is not wearing an anti-G suit.

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.