imported>Patrick: /* Exercise 3 */

2011-08-30T18:22:14Z

Exercise 3

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''Helena Dedic''

'''Beware: Many of the solutions to these exercises use <math>g = 10 m/s^2</math> !'''
 

==Exercise 1==

Consider a 20-g bullet (B) and a 60-kg athlete (A).

(a) If they have the same momentum, what is the ratio of their kinetic energies <math>K_B \over K_A</math>?

(b) If they have the same kinetic energy, what is the ratio of their momenta <math>p_B \over p_A</math>? 

*[[Conservation of Momentum EX 1|SOLUTION EX 1]] 

==Exercise 2==

What is the change of momentum of a particle when a net force of 1000 N pointing in the direction 37° West of North acts on it for one millisecond? 

*[[Conservation of Momentum EX 2|SOLUTION EX 2]] 

==Exercise 3==

The total momentum of a system of three particles has zero y-component. The momentum of the first particle has a magnitude of 96 <math>\tfrac{kg m}{s}</math> and points in the direction of 60° East of South. The momentum of the second particle has a magnitude of 167 <math>\tfrac{kg m}{s}</math> and points in the direction of 53° North of East. The third particle moves in the direction of 60° South of West. Determine the magnitude and the direction of the total momentum of the system and the magnitude of the momentum of the third particle. 

*[[Conservation of Momentum EX 3|SOLUTION EX 3]] 

==Exercise 4==

A 10,000-kg truck moves at 30 m/s. At what speed would a 1200 kg car have the same value of

(a) linear momentum;

(b) kinetic energy? 

*[[Conservation of Momentum EX 4|SOLUTION EX 4]] 

==Exercise 5==

A 6-kg bomb moving at 5 m/s in the direction 37° South of East explodes into three pieces. A 3-kg piece moves off at 2 m/s at 53° North of East while a 2-kg piece moves West at 3 m/s. What is the velocity of the third fragment? Assume all motion occurs in a horizontal plane. 

*[[Conservation of Momentum EX 5|SOLUTION EX 5]] 

==Exercise 6==

A nucleus of radioactive radium (<math>^{226}Ra</math>), initially at rest, decays into a radon nucleus (<math>^{222}Rn</math>) and an <math>\alpha</math> particle (a <math>^{4}He</math>). The kinetic energy of the <math>\alpha</math> particle is <math>6.72 \times 10^{-13} J</math> after the decay. The mass of <math>^{226}Ra</math> is 226 <math>u</math>; the mass of radon is 222 <math>u</math> and the mass of <math>^{4}He</math> is 4 <math>u</math>. You may recall from chemistry that a unified mass unit <math>u = 1.66 \times 10^{-27} kg</math>.

(a) Determine the recoil speed of the radon nucleus.

(b) Determine its kinetic energy. 

*[[Conservation of Momentum EX 6|SOLUTION EX 6]]

Exercises on Conservation of Momentum - Revision history

imported>Patrick: /* Exercise 3 */