3. Mechanics

Dynamics — Quiz

Test your understanding of dynamics with 5 practice questions.

Practice Questions

Question 1

Which physical quantity remains constant in a system of particles if no external forces act?

Question 2

A particle starts from rest with acceleration given by $a(t)=4t^2\,\mathrm{m/s^2}$. What is its speed at $t=3\,\mathrm s$?

Question 3

A mass $A=2\,\mathrm{kg}$ hangs over a frictionless pulley, connected to mass $B=2\,\mathrm{kg}$ on a horizontal table. The coefficient of friction between $B$ and the table is $\mu=0.1$. Take $g=9.8\,\mathrm{m/s^2}$. What is the magnitude of the acceleration of the system?

Question 4

Three particles of masses $1\,\mathrm{kg},2\,\mathrm{kg},3\,\mathrm{kg}$ lie on the $x$-axis at $x=0, x=2, x=5$ respectively. What is the $x$-coordinate of their centre of mass?

Question 5

Which expression correctly applies Newton’s second law to the centre of mass of a system of particles?