Use the relation between kinetic energy

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

Use the relation between kinetic energy, mass, and momentum to answer the following. (a) Show that the kinetic energy of a body of mass

m

and momentum

p

can be expressed as

E_K=\frac{p^2}{2m}

. (b) Calculate the kinetic energy of: (i) a

3.0\,\mathrm{kg}

mass with momentum

12.0\,\mathrm{kg\,m\,s^{-1}}

; (ii) an electron of mass

9.11\times10^{-31}\,\mathrm{kg}

with momentum

5.4\times10^{-24}\,\mathrm{kg\,m\,s^{-1}}

. (c) Calculate the momentum of: (i) a mass of

0.60\,\mathrm{kg}

with

E_K=30.0\,\mathrm{J}

; (ii) a tennis ball of mass

58\,\mathrm{g}

with

E_K=26.1\,\mathrm{J}

. Direction is not required.