弹力ppt复习进程.ppt

F=50NF=50NFEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

第七章第２节弹力Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

力的作用效果知识回顾改变物体形状，使它发生形变改变物体运动状态？Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

恢复到原来形状没有恢复到原来形状弹性形变塑性形变Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

一、弹性、塑性弹簧原状施加外力产生形变停止用力形变消失停止用力形变保留原状施加外力产生形变橡皮泥弹性:物体受力发生形变，撤销外力，能自动恢复到原状塑性:物体受力发生形变，撤销外力，不能自动恢复原状弹性形变塑性形变弹性限度Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

1.弹力：物体由于发生弹性形变而产生的力二、弹力Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

甲乙丙ABBABA哪幅图中，A、B之间有弹力？①物体相互接触②物体相互挤压（发生弹性形变）2、产生条件FBFAEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

有的形变明显、有的形变微小物理方法：转换法Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

3、弹力的种类支持力、压力、拉力等F支F压F拉F推Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

弹簧挂钩三、弹簧测力计刻度盘单位指针（测力工具）Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

在弹性限度内，弹簧的伸长量与它受到的拉力成正比三、弹簧测力计1.原理：Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

F1=2NF2=4NF3=6NL0=5cmL1=6cmL2=7cmL3=8cm1cm3cm2cmEvaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientProfile5.2.0.0.Copyright2004-2011AsposePtyLtd.

（1）观察:（2）检查（3）测量（4）读记：示数表示钩上所受拉力的大小2、使用方法：调零沿弹簧的轴线方向轻拉几次不能超量程力的方向要与弹簧轴线方向一致物体要保持静止或匀速直线运动量程、分度值视线与刻度板垂直1.弹簧弹性3.归零2.摩擦Evaluationonly.CreatedwithAspose.Slidesfor.NET3.5ClientP