Chapter 4 - Force and Motion - Learning Path Questions and Exercises - Exercises - Page 140: 86

a). Second case. b). $w$ c). $a=1306m/s^{2}$ $F=133.3w$

a). The ball exerts more force in the case when it is allowed to from a height. In this case also, the ball is likely to dent the floor. b). In case of ball resting on the surface, the force it exerts is simply the weight, w. c). $v=\sqrt (u^{2}+2gS)=\sqrt (0+2\times9.8\times2)=6.26m/s$ Thus, $a=\frac{v^{2}-u^{2}}{2s}=\frac{-6.26^{2}}{2\times0.015}=1306m/s^{2}$ Thus, $F=ma=\frac{w}{g}{a}=\frac{1306}{9.8}w=133.3w$