/*! 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 46 \(\bullet\) Dynamite! A demoliti... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

\(\bullet\) Dynamite! A demolition crew uses dynamite to blow an old building apart. Debris from the explosion flies off in all directions and is later found at distances as far as 50 \(\mathrm{m}\) from the explosion. Estimate the maximum speed at which debris was blown outward by the explosion. Describe any assumptions that you make.

Short Answer

Expert verified
The maximum speed of the debris is approximately 22.14 m/s.

Step by step solution

01

Identify known quantities

We are given that the maximum distance debris is found from the explosion is 50 meters. We need to estimate the maximum speed at which debris was blown outward. The acceleration due to gravity, \( g \), is approximately 9.8 m/s², which will be relevant for calculating the time it takes for debris to travel upward.
02

Make simplifying assumptions

Assume that the debris follows a projectile motion, launched at an optimal angle of 45 degrees for maximum range. Also, assume there's no air resistance and the explosion has an immediate impact, giving the debris an initial speed. The debris lands at the same elevation it was launched from.
03

Use range formula for projectile motion

The range \( R \) of a projectile launched at an initial velocity \( v_0 \) and angle \( \theta \) is given by: \[R = \frac{v_0^2 \sin(2\theta)}{g}\].Given that \( R = 50 \mathrm{m} \) and \( \theta = 45^\circ \), we have \( \sin(2\theta) = \sin(90^\circ) = 1 \).
04

Solve for initial velocity

Plug the known values into the range formula:\[50 = \frac{v_0^2}{9.8}\]Solving for \( v_0 \), we find:\[v_0^2 = 50 \times 9.8 \]\[v_0^2 = 490\]\[v_0 = \sqrt{490} \approx 22.14 \mathrm{m/s}\]
05

State any necessary assumptions clearly

Our calculation assumes no air resistance, an optimal launch angle for maximum range, and that the explosion provided an immediate initial velocity to the debris. We also assumed the point of launch and landing are at the same height.

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.

Demolition
In the context of demolitions, which involve tearing down buildings or structures, dynamite plays a crucial role. The main goal is to safely bring down the structure while minimizing the impact on the surrounding environment. Demolition teams use controlled explosions to direct the force in specific ways, with plans that include timing and the placement of explosive charges. These intricacies ensure that the structure collapses inward, reducing collateral damage.
  • Precision is key in demolition to avoid unwanted damage to nearby buildings.
  • Explosions must be controlled to ensure safety and effectiveness.
  • Understanding projectile motion helps in predicting where debris will land.
In this exercise, maths and physics help determine factors like the velocity and trajectory of debris during a controlled demolition using dynamite.
Dynamite
Dynamite, invented by Alfred Nobel, is a highly effective explosive. It is often used in demolitions due to its rapid expansion force, which can break apart materials such as concrete and steel. When detonated, dynamite releases gases at high speed and pressure, pushing debris outward in all directions. This rapid expansion is why dynamite is a popular choice in demolition work.
  • Dynamite consists of nitroglycerin, an unstable explosive component.
  • Stability is improved with absorption in materials like diatomaceous earth.
  • Safety protocols are crucial when handling dynamite during demolitions.
Knowing the effects of dynamite helps demolition crews predict and calculate the force needed to achieve results safely. This understanding is integral when calculating initial velocity in projectile motion.
Initial Velocity
Initial velocity is a vital concept in physics, especially in projectile motion. It refers to the speed of an object at the start of its trajectory. During a demolition, the debris is given an initial burst of speed from the explosion. This initial speed is crucial for estimating how far the debris will travel. By understanding initial velocity, we can apply formulas to predict movement.
  • The initial speed determines the maximum distance for debris spread.
  • In our scenario, initial velocity can be calculated using the range formula.
  • Factors affecting initial velocity include the force of the explosion and the mass of the debris.
This concept allows us to estimate speeds like the debris' velocity from where it lands – crucial for safety and planning in demolition works.
Range Formula
The range formula is an essential tool for solving problems involving projectile motion. This formula helps us calculate how far an object will travel when launched at a particular angle and speed. It is especially useful in demolition as it allows professionals to predict how debris will spread from an explosion. The formula is defined as: \[R = \frac{v_0^2 \sin(2\theta)}{g}\] where \(R\) is the range, \(v_0\) is the initial velocity, \(\theta\) is the angle of launch, and \(g\) is the acceleration due to gravity. For maximum range, the angle is typically 45 degrees since \(\sin(90\degree)=1\).
  • Assuming no air resistance simplifies the calculations.
  • This formula is crucial for predicting debris landing areas.
  • Understanding this helps adjust demolition strategies appropriately.
Utilizing the range formula in demolitions provides insight into the physics behind explosions, enabling safer and more efficient workflows.

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

\cdots An airplane is flying with a velocity of 90.0 \(\mathrm{m} / \mathrm{s}\) at an angle of \(23.0^{\circ}\) above the horizontal. When the plane is 114 \(\mathrm{m}\) directly above a dog that is standing on level ground, a suitcase drops out of the lugage compartment. How far from the dog will the suitcase land? You can ignore air resistance.

Inside a star ship at rest on the earth, a ball rolls off the top of a horizontal table and lands a distance \(D\) from the foot of the table. This star ship now lands on the unexplored Planet \(X\) . The commander, Captain Curious, rolls the same ball off the same table with the same initial speed as on earth and finds that it lands a distance 2.76\(D\) from the foot of the table. What is the acceleration due to gravity on Planet \(\mathrm{X}\) ?

\(\cdot\) A model of a helicopter rotor has four blades, each 3.40 \(\mathrm{m}\) in length from the central shaft to the tip of the blade. The model is rotated in a wind tunnel at 550 rev/min. (a) What is the linear speed, in \(\mathrm{m} / \mathrm{s}\) , of the blade tip? (b) What is the radial acceleration of the blade tip, expressed as a multiple of the acceleration \(g\) due to gravity?

. A man stands on the roof of a 15.0 -m-tall building and throws a rock with a velocity of magnitude 30.0 \(\mathrm{m} / \mathrm{s}\) at an angle of \(33.0^{\circ}\) above the horizontal. You can ignore air resistance. Calculate (a) the maximum height above the roof reached by the rock, (b) the magnitude of the velocity of the rock just before it strikes the ground, and (c) the horizontal distance from the base of the building to the point where the rock strikes the ground.

. A water hose is used to fill a large cylindrical storage tank of diameter \(D\) and height 2\(D\) The hose shoots the water at \(45^{\circ}\) above the horizontal from the same level as the base of the tank and is a distance 6\(D\) away (Fig. \(3.43 ) .\) For what range of launch speeds \(\left(v_{0}\right)\) will the water enter the tank? Ignore air resistance, and express your answer in terms of \(D\) and \(g .\)

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.