I simplified a person walking into just an electro mechanical foot. The force is applied to the foot to move it due to a battery powering the foot — so internal force
What I mean is that there is a mechanical foot that moves the same way a real foot moves but is powered electrically. The foot starts at zero velocity and then pushes down on the ground, causing the foot to slide backwards, but if we analyze the free body diagram of the foot, the foot should...
What if the system is just for example a mechanical/electrical foot that moves and slips on the floor. As the foot pushes down and back on the ground, shouldn't the foot be slipping backwards, but according to the free body diagram, the foot should just be propelling forward due to the kinetic...
Ok, then how come with the free body diagram of this simplified system (a person slipping on the floor represented as just a foot in the image below), there seems to be only a forward force, the kinetic friction, propelling the foot forward, but the leg should be overall moving backward due to...
If we draw the free body diagram of a person walking with the feet slipping, we have kinetic friction applied to the feet. Is this kinetic friction going to propel the person forward? For example if the person tries to walk on ice, the foot just slips and the person doesn’t get propelled forward...
Could you explain that in simpler terms please? I get the angular momentum change = net moment. But then got lost afterwards. I am looking at the block in terms of statics though and you seem to be talking about it in terms of dynamics?
I am thinking about this and wondering whether the drag force is what causes the block to tip, so in a vacuum, if you slide a cloth underneath the block from right to left, there should be no tipping.
If I slide a cloth from right to left underneath a block, what is the compensating horizontal force on the CM?
Are you saying that sliding a cloth underneath the block would make it rotate ccw?
The fbd is for a cloth sliding out from the bottom of the block.
If the block rotates ccw, shouldn’t the normal force be on the bottom right of the block instead?
Correction: If the block rotates ccw, the normal force should be the bottom left of the block.
This doesn’t answer my question that...
For this freebody diagram showing a cloth being pulled from underneath a block, if we take the moment about the normal force:
m*g*L/2 = 0, there is no force counteracting the moment from the weight of the block.
But if we take the moment about the center of gravity:
N*L/2 - Ff*H/2 = 0
How do...
So you think the way I have defined ##\theta## is clockwise b/c we are measuring the angle from the horizontal to the pendulum string correct? How come we cannot measure the angle from the pendulum string to the horizontal and say that ##\theta## is defined counterclockwise (the way I have the...
I think you meant to say ##\vec i## has to be pointing to the right and ##\vec j## has to be pointing up.
That is interesting that the ##\frac{dn_1}{dt}## and ##\frac{dn_2}{dt}## ended up that way. In order for my way of calculating them to be true, we would have to be rotating clockwise so...
For this ##\dot{\vec n_1}## and ##\dot{\vec n_2}## I have them negated.
##\dot{\vec n_1} = \dot{\theta}\vec k \times \vec n_1 = \dot{\theta}\vec n_2## where ##\vec k## is pointing out of the screen and ##\vec n_1 \times \vec n_2 = \vec k##.
##\dot{\vec n_2} = \dot{\theta}\vec k \times \vec n_2 =...