Question

一物体静止在水平面上，其质量为2kg，物体与地面之间的动摩擦因数为0.5，给物体施加一水平向右的拉力，拉力大小为20N．求：                                                                                                                

（1）物体的加速度为多大？                                                                                     

（2）2s末物体的速度为多大？                                                                                  

                                                                                          

                                                                                                                                 

Answer 1

（1）根据牛顿第二定律：F﹣μmg=ma

得：a==5m/s²

（2）根据匀变速直线运动的速度时间公式：v=at=2×5=10m/s

答：（1）物体的加速度为5m/s²；

（2）2s末物体的速度为10m/s．