Energy!

Classical Mechanics Level 1

Find the momentum of a body of mass $100\text{ g}$ having a kinetic energy of $20 \text{ J}$ .

Hint: the S.I. units of momentum are $\dfrac{Kg \cdot m}{s}$ .

4 solutions

Vishal S
Jan 3, 2015

K.E.=1/2mv^2, here m=mass & v=velocity

by substituting the given values,we get

20=1/2 x 1/10 x v^2

=>20=1/20 x v^2

=>v=20

Momentum =mv

by substituting, we get

Momentum=1/10 x 20=2

therefore momentum of a body when it's K.E. = 20 and mass = 100g is 2kgms^-1

right vishal s

sumita cardio - 6 years, 5 months ago

Ssk Sk
Jan 10, 2015

Convert mass in to SI unit Therefore mass = 10^-1

KE=1/2mv^2.

So substituting KE & mass, We get velocity I.e. 20

Momentum (P)=MV= 10^-1 x 20 = 2

Shakil Md Resvy
Jan 3, 2015

K.e=1/2mv^2.mv^2=20, v^2=40, v=20, mv=20×0.1=2

yes i agreed with u #Shakil Md resvy.......RIGHT ANSWER

sumita cardio - 6 years, 5 months ago

Pranav Patil
Jan 13, 2015

kinetic energy in terms of momentum is p^2/2m ......................easily gives answer.