质量为m，长为1，通有电流I的导体棒静止在水平轨道上，匀强磁场的磁感强度为B，其方向为与棒垂直，与轨道面成θ角斜向上，此时棒受到的摩擦力为______，受到的支持力可能是______．
棒的受力分析图如图所示：
由安培力公式，有：
F=BIL
由共点力平衡条件，有：
Fsinθ=Ff
FN+Fcosθ=mg
整理得：
Ff=BILsinθ
FN=mg-BILcosθ
故答案为：BILsinθ；mg-BILcosθ．
Like any good mother, when Karen found out that another was on the way, she did what she could to help her three-year-old son, Michael, for a new life. They found out that the new baby was going to be a girl, and every day Michael sang to his in Mommy’s tummy. The days went by. The little girl got after the birth. The doctor told the parents, “There is very hope. Be prepared for the worst.” They had fixed up a special in their home for the new baby, but now they a funeral. Michael kept begging his parents to let him see his sister. “I want to to her,” he said. If he didn’t see sister now, he might never see her . She dressed him in an oversized suit and marched him into ICU, but the head nurse him as a child and shouted. “Get the kid out of here now! No children are .” The mother rose up strong, and the mild-mannered lady glared steel-eyed into the head nurse’s face. “He is not leaving he sings to his sister!” Karen towed Michael to his sister’s bedside. He gazed at the tiny infant the battle to live, and he began to sing. In the pure voice of a 3-year-old, Michael sang: “You are my sunshine, my only sunshine. You make me happy when skies are gray....” Instantly the baby girl . The pulse rate became calm and steady. “You never know, dear, how much I love you. Please don’t take my away.” “The other night, dear, as I lay sleeping, I I held you in my arms.....” Michael’s little sister relaxed. The medical staff just called it a miracle. Karen called it a miracle of God’s ! NEVER GIVE UP ON THE PEOPLE YOU LOVE. LOVE IS SO POWERFUL.
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