At 7:14A.M. on June 30,1908, a huge explosion 1 occurred above remote central Siberia, at latitude 61°Nand longitude 102°E; the fireball thus created was the brightest flash seen by anyone before nuclear weapons. The Tunguska Event, which according to one chance witness “covered an enormous part of the sky,” was probably the explosion of a stony asteroid about140m wide. (a) Considering only Earth’s rotation, determine how much later the asteroid would have had to arrive to put the explosion above Helsinki at longitude 25°E. This would have obliterated the city. (b) If the asteroid had, instead, been a metallic asteroid, it could have reached Earth’s surface. How much later would such an asteroid have had to arrive to put the impact in the Atlantic Ocean at longitude20°W ? (The resulting tsunamis would have wiped out coastal civilization on both sides of the Atlantic.)

Short Answer

Expert verified

a) Time taken by the asteroid to arrive to put explosion above Helsinki at longitude 250E ist=5.1 h .

b) Time taken by the asteroid to arrive to put impact in the Atlantic Ocean at longitude200 W is t=8.1h.

Step by step solution

01

Given

Coordinates of explosion -(61° N,102° E)

02

Understanding the concept

Use the concept of angular velocity and angular displacement. First, find angular displacement and then, using the speed of earth, find the time taken by the asteroid to arrive to put in the explosion.

Formulae:

ω=θt

03

(a) Calculate how much later the asteroid would have had to arrive

Time taken by the asteroid to arrive to put explosion above Helsinki at longitude 250E:

First we find angular separation:

ω=1 rev1 day=360o24 h

Angular velocity of earth in one day:

ω=1 rev1 day=360o24 h

Time taken for 1 day:

ω=θt

t=θω=77o360o24=5.13 h

t=5.13 h5.1 h

04

(b) Calculate how much later would such an asteroid have had to arrive if the asteroid had been metallic

Time taken by the asteroid to arrive to put impact in the Atlantic Ocean at longitude200 W:

Similarly, angular separation for this is

θ=θ2θ1=102o(20o)=122o

Time taken for 1 day:

ω=θt

t=θω=1220360024=8.13 h

t=8.13t8.1 h

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 Vaia!

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 wheel, starting from rest, rotates with a constant angular acceleration of 2.00rad/s2. During a certain 3.00sinterval, it turns through 90.0rad. (a) What is the angular velocity of the wheel at the start of the3.00sinterval? (b) How long has the wheel been turning before the start of the3.00sinterval?

In Fig.1045a , an irregularly shaped plastic plate with uniform thickness and density (mass per unit volume) is to be rotated around an axle that is perpendicular to the plate face and through point O. The rotational inertia of the plate about that axle is measured with the following method. A circular disk of mass0.500 kg and radius2.00 cm is glued to the plate, with its center aligned with point O(Fig.1045b ). A string is wrapped around the edge of the disk the way a string is wrapped around a top. Then the string is pulled for 5.00 s. As a result, the disk and plate are rotated by a constant force of 0.400 Nthat is applied by the string tangentially to the edge of the disk. The resulting angular speed is 114 rad/s. What is the rotational inertia of the plate about the axle?

What is the angular speed of (a) the second hand, (b) the minute hand, and (c) the hour hand of a smoothly running analog watch? Answer in radians per second.

The flywheel of an engine is rotating at25.0rads . When the engine is turned off, the flywheel slows at a constant rate and stops in1.0s . Calculate

(a) The angular acceleration of the flywheel,

(b) The angle through which the flywheel rotates in stopping, and

(c) The number of revolutions made by the flywheel in stopping

A uniform helicopter rotor blade is 7.80mlong, has a mass of110kg , and is attached to the rotor axle by a single bolt. (a) What is the magnitude of the force on the bolt from the axle when the rotor is turning at320rev/min? (Hint: For this calculation the blade can be considered to be a point mass at its center of mass. Why?) (b) Calculate the torque that must be applied to the rotor to bring it to full speed from rest in6.70s . Ignore air resistance. (The blade cannot be considered to be a point mass for this calculation. Why not? Assume the mass distribution of a uniform thin rod.) (c) How much work does the torque do on the blade in order for the blade to reach a speed of 320rev/min?

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.

Sign-up for free