/*! 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 28 At the Earth's surface a project... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

At the Earth's surface a projectile is launched straight up at a speed of \(10.0 \mathrm{km} / \mathrm{s} .\) To what height will it rise? Ignore air resistance and the rotation of the Earth.

Short Answer

Expert verified
The maximum height the projectile reaches is approximately \(510.20 \mathrm{km}\).

Step by step solution

01

Understanding Given and What to Find

A projectile is launched straight up with initial velocity of \(10.0 \mathrm{km} / \mathrm{s}\) or \(10000 \mathrm{m} / \mathrm{s}\). The acceleration due to gravity (\(g\)) is \(9.8 \mathrm{m} / \mathrm{s}^2\), directed downwards. As the projectile goes up, gravity decelerates it. We need to find the maximum height the projectile will reach, which occurs when its velocity becomes zero.
02

Applying Second Equation of Motion

The second equation of motion that relates final velocity (\(v\)), initial velocity (\(u\)), acceleration (\(a\)), and distance (\(s\)) is: \(v^2 = u^2 + 2as\). Since the final velocity at maximum height is zero (we're assuming that the maximum height is reached when projectile speed is zero), this simplifies to: \(0 = u^2 + 2as\). Rearranging for the displacement (\(s\)), we get \(s = -u^2 / 2a\).
03

Substitute Known Values

Substitute \(u = 10000 \mathrm{m} / \mathrm{s}\) and \(a = -9.8 \mathrm{m} / \mathrm{s}^2\) (the negative sign indicates that gravity is acting downwards, decelerating the projectile) to find the maximum height; \(s = -((10000)^2) / (2*-9.8)\).
04

Calculate the Maximum Height

Evaluating the expression by using calculator we get \(s = 510204.08 \mathrm{m}\). However, as the question ask the height in kilometers, converting the unit; \(s = 510.20 \mathrm{km}\).

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.

Initial Velocity
Initial velocity is the speed with which an object begins its movement. In projectile motion, it plays a critical role in determining how high or far the object will travel. For instance, in our exercise, the projectile is launched straight up with an initial velocity of \(10000 \, \text{m/s}\). This high speed is crucial as it provides the projectile the energy it needs to overcome the downward pull of gravity and ascend to a maximum height.
Understanding initial velocity allows us to predict the trajectory of any projectile. It often acts as a primary input in motion equations and is crucial for experimenting with different launch scenarios. The initial speed and the angle at which an object is launched can significantly affect its flight path. This is why initial velocity is a fundamental concept in studying motion.
Acceleration Due to Gravity
Acceleration due to gravity, denoted by \(g\), is the rate at which an object accelerates due to Earth's gravitational pull. At the Earth's surface, this value is approximately \(9.8 \, \text{m/s}^2\). It acts in the downward direction, opposing any upward motion of a projectile.
In our situation, as the projectile is launched upward, gravity slows it down until it reaches its maximum height. Gravity ensures the projectile eventually stops rising and begins falling back down. It's important because it provides a constant deceleration force in upward motion and acceleration when coming back down.
  • Always directed downward.
  • Consistent and predictable, valuable for calculations.
  • A critical factor in determining time of flight and maximum altitude.
Maximum Height
The maximum height of a projectile is the peak point reached during its flight path. At this position, the vertical velocity becomes zero, marking the transition from upward motion to a downward fall.
To determine the maximum height, we use the equations of motion. In our exercise, the equation \(v^2 = u^2 + 2as\) simplifies to \(0 = 10000^2 + 2 (-9.8) s\) when the final velocity \(v = 0\). Rearranging gives the displacement \(s = -u^2 / 2a\), resulting in a calculated height of approximately \(510.20 \, \text{km}\).
This value tells us how high the projectile can soar based on its initial velocity and gravitational pull. It is essential for trajectory planning and understanding the limits of vertical motion.
Equations of Motion
Equations of motion are mathematical formulas used to calculate the variables of moving objects, such as velocity, acceleration, and displacement. In projectile motion, these equations are invaluable tools for predicting the flight path and behavior of launched objects.
A key equation from our example is \(v^2 = u^2 + 2 a s\), where \(v\) is the final velocity, \(u\) is the initial velocity, \(a\) is the acceleration (due to gravity, in this case), and \(s\) is the displacement or height reached. Using this formula allowed us to find the maximum height the projectile achieves.
  • Apply them to solve for unknown variables.
  • Help visualize motion over time.
  • Essential for understanding both the theoretical and practical aspects of dynamics and kinematics.
These equations form the backbone of motion analysis and are crucial for anyone studying physics or engineering.

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

A certain quaternary star system consists of three stars, each of mass \(m,\) moving in the same circular orbit of radius \(r\) about a central star of mass \(M .\) The stars orbit in the same sense, and are positioned one third of a revolution apart from each other. Show that the period of each of the three stars is given by $$T=2 \pi \sqrt{\frac{r^{3}}{g(M+m / \sqrt{3})}}$$

In introductory physics laboratories, a typical Cavendish balance for measuring the gravitational constant \(G\) uses lead spheres with masses of \(1.50 \mathrm{kg}\) and \(15.0 \mathrm{g}\) whose centers are separated by about \(4.50 \mathrm{cm} .\) Calculate the gravitational force between these spheres, treating each as a particle located at the center of the sphere.

An object is fired vertically upward from the surface of the Earth (of radius \(R_{E}\) ) with an initial speed \(v_{i}\) that is comparable to but less than the escape speed \(v_{\text {esc. }}\) (a) Show that the object attains a maximum height \(h\) given by $$h=\frac{R_{E} v_{i}^{2}}{v_{\mathrm{esc}}^{2}-v_{i}^{2}}$$ (b) A space vehicle is launched vertically upward from the Earth's surface with an initial speed of \(8.76 \mathrm{km} / \mathrm{s}\), which is less than the escape speed of \(11.2 \mathrm{km} / \mathrm{s} .\) What maximum height does it attain? (c) A meteorite falls toward the Earth. It is essentially at rest with respect to the Earth when it is at a height of \(2.51 \times 10^{7} \mathrm{m} .\) With what speed does the meteorite strike the Earth? (d) What If? Assume that a baseball is tossed up with an initial speed that is very small compared to the escape speed. Show that the equation from part (a) is consistent with Equation 4.13.

A satellite of mass \(m,\) originally on the surface of the Earth, is placed into Earth orbit at an altitude \(h\). (a) With a circular orbit, how long does the satellite take to complete one orbit? (b) What is the satellite's speed? (c) What is the minimum energy input necessary to place this satellite in orbit? Ignore air resistance but include the effect of the planet's daily rotation. At what location on the Earth's surface and in what direction should the satellite be launched to minimize the required energy investment? Represent the mass and radius of the Earth as \(M_{E}\) and \(R_{E}\).

Determine the order of magnitude of the gravitational force that you exert on another person \(2 \mathrm{m}\) away. In your solution state the quantities you measure or estimate and their values.

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.