friction force on the rack Fr------------------wheel force on the rack在工程机械上是什么意思?

friction force on the rack Fr------------------wheel force on the rack在工程机械上是什么意思? adams 中怎么表示摩擦力?adams 2005 中怎么表示摩擦力?“friction force ：coulombcoulomb friction：on 《===这里的on是什么意思?static corfficient ：0.3dynamic corfficient ：0.1stiction transition vel.：0.1friction transition a 4kg body is placed on horizontal ground.The coefficient of dynamic friction between the body and the ground is 0,2.The object is acted upon by a force of 30 N that encloses an angle of 20 with horizontal.Find the friction force and the acceleration 一道英文物理题A 4kg body is placed on horizontal ground.The coefficient of dynamic friction between the body and the ground is 0,2.The object is acted upon by a force of 30 N that encloses an angles of 20 whith horizontal.Find the friction for You pull horizontally on a 50-kg crYou pull horizontally on a 50-kg crate with a force of 350N and the friction force on the crate is 250N.The acceleration of the crate is 选项A7m/s平方B1m/s平方C12m/s平方D2m/s平方.给评价的 friction is a force that always acts an opposition movementopposition movement又是什么? 200分求数学题 求过程A block of steel on a level, frozen pond, is given an initial speed V. Even though the block of steel issliding on smooth ice, there will be a small friction force that will slow the block of steel until itcomes to a stop. 问一道力学物理题（英文）Two people are pulling a canoe on a friction surface,person A pulls at 60N{20度}and person B pulls at 60N{40度},calculate the force.请各位帮忙滴朋友一定告知完整步骤,中文即可, 什么物理实验,目的,原理Static and Kinetic FrictionIf you try to slide a heavy box resting on the floor,you may find it difficult to get the box moving.Static friction is the force that is acting against the box.If you apply a light horizonta 什么物理实验,目的,原理Static and Kinetic FrictionIf you try to slide a heavy box resting on the floor,you may find it difficult to get the box moving.Static friction is the force that is acting against the box.If you apply a light horizonta 英语翻译1.what is the formula for momentum,and is it a vector?2.Briefly state Newton's Third Law.3.If a box is sliding to the right,direction is the force of friction on the box?4.Name one difference between mass and weight. while one end of the board is being raised,what is the effect on the force of friction between the board and the object?答案给的是steadily increases为啥呢?回复一楼的：没有图,它属于前几题的 不好意思补充下：前面题设 英语翻译Slow Down You know that when you hit a baseball high into the air ,it comes down because of gravity .After it hits the ground ,the ball bounces,slow down ,and comes to a stop .Why doesn’t it just keep on rolling A force called friction 英语翻译谁能帮我翻译 我会将我全部分送出全文如下：Air force one and the farmer Air Force One crashed in the middle of rural America.Panic stricken,the Secret Service mobilized and descended on the farm in force.When they got th force force force Were it not for friction ,we were not able to walk on this earth of ours.were,for friction,were not able to,of ours哪个错了.