A110. g wooden block is initially at rest on a rough horizontal surface when a 12.8 g bullet is fired horizontally into (but does not go through) it. after the impact, the block–bullet combination slides 6.5 m before coming to rest. if the coefficient of kinetic friction between block and surface is 0.750, determine the speed of the bullet (in m/s) immediately before impact.

94 ms⁻¹

Explanation:

= Speed of the bullet-block combination after collision

= distance traveled by the combination before coming to stop = 6.5 m

= Coefficient of kinetic friction = 0.750

acceleration due to friction on a flat surface can be given as

= Final speed of the combination = 0 m/s

Based on the above equation , we can use the kinematics equation as

= mass of the wooden block = 110 g

= mass of the bullet = 12.8 g

= Speed of the bullet before collision

Using conservation of momentum for inelastic collision , we have

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )