MYTUTOR SUBJECT ANSWERS

174 views

Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together. What is the speed of the trucks after the collision?

In order to solve this question we need to use the principle of conservation of momentum which states:

The momentum in a closed system remains constant before and after a collision or explosion.

I.E.

momentum before=momentum after

And ingeneral momentum is calculated using: P=mv where P is the momentum, m is the mass of the object, and v is the velocity of the object.

Hence the total momentum before the collision is:

P1+P2

=m x 2v + 3m x -v       NOTE: notice the negative v on the second truck as it is moving in the opposite direction to the first truck

=-mv

After the collision the the trucks stick together so the total mass becomes 4m and the combined trucks move at an unknown speed of v​after

We will solve the equation for conservation of momentum to determine vafter​:

mv=4mvafter

cancelling out the m's:

v=4vafter

and rearranging to make v​after the subject of the equation:

vafter​=0.25v

Which is our final answer.

Sarah W. A Level Maths tutor, GCSE Maths tutor, A Level Chemistry tut...

2 months ago

Answered by Sarah, an A Level Physics tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist

46 SUBJECT SPECIALISTS

£24 /hr

Dorian A.

Degree: Theoretical Physics (Masters) - Durham University

Subjects offered: Physics, Maths+ 1 more

Physics
Maths
Further Mathematics

“About Me As a Theoretical Physics student at Durham University, I am more than aware of all of the confusing turns that science can take. I have areal passion for my subject, and hope to show my students howbeautiful science can be.  ...”

£30 /hr

Fahad M.

Degree: Medicine And Surgery - MBChB (Bachelors) - Birmingham University

Subjects offered: Physics, Psychology+ 7 more

Physics
Psychology
Maths
Chemistry
Biology
.UKCAT.
.BMAT (BioMedical Admissions)
-Personal Statements-
-Medical School Preparation-

“About MeGraduating highschool with many distinctions I went on to become a medical student at the University of Birmingham. Having excelled in my interview (gaining the top rank in Motivation and Experience) I went on immediately to ...”

£22 /hr

Hayden M.

Degree: Physics (Masters) - Warwick University

Subjects offered: Physics, Science+ 4 more

Physics
Science
Maths
Further Mathematics
English
Chemistry

“My name is Hayden. I am a 2nd year Physics student at The University of Warwick. I get excited aboutall things science and I hope that I can help you not only learn your material but alsounderstand why it is a useful thing to know.A...”

About the author

Sarah W.

Currently unavailable: for new students

Degree: Robotics (Masters) - Bristol University

Subjects offered: Physics, Maths+ 3 more

Physics
Maths
Electronics
Chemistry
Biology

“About Me: I am currently a Masters student in Robotics at the University of Bristol. My choice of degree was based on my love for hands on science. I will try to pass on this love to you during my tutorials! I have alot of experience...”

You may also like...

Posts by Sarah

How could I write a program to convert Km/h to m/s in python

How do you solve 3sin2AtanA=2 for 0<A<180?

In the presence of ultraviolet light, ethane and chlorine react to give a mixture of products. What are the products of this reaction?

Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together. What is the speed of the trucks after the collision?

Other A Level Physics questions

What is the difference between a scalar and a vector? Give 3 examples of each.

Why is the centripetal force necessary for circular motion?

Resolving the forces for an object suspended on two strings.

What is the main evidence for the Big Bang theory?

View A Level Physics tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok