关于曲线运动,下列说法正确的是(    )  A、 物体在恒力作用

 关于曲线运动,下列说法正确的是(    ) 

A、 物体在恒力作用下不可能做曲线运动

B、 物体在变力作用下一定做曲线运动

C、 做曲线运动的物体,其速度大小可能不变

D、 速度大小和加速度大小均不变的运动不可能是曲线运动

 

答案

 C     

 

相关题目

 Because our conscious mind is occupied with daily life we don’t always thin
 Because our conscious mind is occupied with daily life we don’t always think about the emotional significance of the day’s events—_______, it appears, we begin to dream. A. because     
定积分           .    
定积分           .    
肽键在下列哪两个基团之间形成的?   A.磷酸基和羧基     
肽键在下列哪两个基团之间形成的?   A.磷酸基和羧基       B.羧基和氨基         C.醇基和醛基       D.醛基和氨基
雅典民主政治发展的过程中,具有否定血缘关系的改革措施
雅典民主政治发展的过程中,具有否定血缘关系的改革措施有 ①按财产的多寡划分社会等级  ②按地域划分部落  ③按公民大会的决议决定内政外交 
----- Hi, Mark. How was the musical evening?   ----- Excellent! Ales and Andy p
----- Hi, Mark. How was the musical evening?   ----- Excellent! Ales and Andy performed _________ and they won the firs prize.   A. skillfully          B. commonly       C. willingly
 It was necessary to _____ the factory building as the company was doing more a
 It was necessary to _____ the factory building as the company was doing more and more business.    A. extend    B. increase    C. lengthen    D. magnify  
That’s not      picture.      is on the desk. A.his; his’sB.he
That’s not      picture.      is on the desk. A.his; his’sB.her; hersC.hers; herD.yours; yours
第一电离能I1是指气态原子X(g)处于基态时,失去一个电子
第一电离能I1是指气态原子X(g)处于基态时,失去一个电子成为气态阳离子X+(g)所需的能量。下图是部分元素原子的第一电离能I1随原子序数变化的

最新题目