The impact strength of a material is an index of its ___________________?
		A. toughness
B. tensile strength
C. capability of being cold worked
D. hardness
E. fatigue strength
		A. toughness
B. tensile strength
C. capability of being cold worked
D. hardness
E. fatigue strength
		A. one-fourth of the total height above base
B. one-third of the total height above base
C. one-half of the total height above base
D. three-eighth of the total height above the base
E. none of the above
		A. h/2
B. J/3
C. h/6
D. h/4
E. 3/i/5
		A. impact energy
B. resilience
C. proof resilience
D. modulus of resilience
E. toughness
		A. maximum calculated value
B. minimum calculated value
C. mean value
D. extreme value
E. none of the above
		A. coplanar non-concurrent forces
B. non-coplanar concurrent forces
C. non-coplanar non-concurrent forces
D. intersecting forces
E. none of the above
		A. balance each other
B. constitute a moment
C. constitute a couple
D. constitute a moment of couple
E. constitute a resultant couple