Tagged Questions
1
vote
0answers
37 views
Why the screwdriver roll?
I am trying my level best to give this screwdriver a vertical push only, but it is going in a circular path. I thought of uneven friction due to non-uniform normal reaction...what do you think? I have ...
0
votes
1answer
33 views
Find the bending moment of a pole attached to a moving block
I'm having trouble with the following problem.
What I've done so far:
x-y is the usual coordinate system.
$a=\frac{F}{m}=\frac{800}{60}$ and the y component of this is $a_y=a\sin{60^\circ}$.
To ...
1
vote
1answer
117 views
Calculating the acceleration of a car
I'm trying to calculate the maximum acceleration a car can achieve with the current gear ratio. I am ignoring drag forces and friction to keep it simple.
I'm doing this by:
calculating the torque ...
1
vote
0answers
38 views
Truck driven from a small motor that can carry a heavy load, yet can travel fast.
I am building a truck from trash as materials. I have one small motor and a a few small gears, but no other engineered materials are allowed. The truck must carry a load for a distance of 3m. The ...
1
vote
0answers
86 views
How much force is required to hold an umbrella?
Assuming a small umbrella (e.g. http://www.amazon.com/ShedRain-WindPro-Umbrella-Close-Size/dp/B001DL5WN0). What are the factors that need to be considered? I assume where I hold the umbrella might ...
1
vote
1answer
112 views
Force and Torque Question on an isolated system
If there's a rigid rod in space, and you give some external force perpendicular to the rod at one of the ends for a short time, what happens?
Specifically:
What dependence does the moment of inertia ...
0
votes
0answers
194 views
Torque required to rotate Drum [closed]
What Torque will require to rotate a Drum about horizontal axis XX.
Drum is filled with industrial Oil.
Weight of filled drum is $W=300 kg$.
Length of Drum $(L)=900mm$
and Diameter of Drum is ...
0
votes
0answers
140 views
Torque required to rotate sand mixer [closed]
the given data is-
Mixer having one impeller(rotor) rotating in horizontal plane about vertical axis.
capacity of mixer to design $C = 250kg$
rotor dia. $D = 45" = 1143mm$
friction coefficient ...
0
votes
0answers
301 views
How to find Rotational and Translational Equilibrium of Hanging Masses on a Bar?
I am making a hanging mobile which needs to be done mathematically by calculating torque. The problem is, I can't seem to figure out how to solve for the distance of the two masses from the pivot ...
0
votes
2answers
769 views
Confused on how to properly use right hand rule
I am having trouble using the right hand rule properly and often find myself putting my hand in awkward orientations. I know you point your hand in the direction of $r$ and then point your fingers in ...
2
votes
1answer
62 views
How does the weight force distribute in roughly kite like kinematic to determine torques
I have a kinematic model like the simplified following image. Assume that all points are fixed. I'm interested in how the force $\vec{m}$ distributes across $a_2$ and $b_2$ up to $a_1$ and $b_1$.
...
0
votes
2answers
235 views
Force applied off center on an object
Assume there is a rigid body in deep space with mass $m$ and moment of inertia $I$. A force that varies with time, $F(t)$, is applied to the body off-center at a distance $r$ from its center of mass. ...
0
votes
1answer
277 views
Torque and equilibrium
I am a little stuck on the concept involved in part b) of the following problem:
A $5 m$ long road gate has a mass of $m = 15 kg$. The mass is evenly distributed in the gate. The gate is supported at ...
3
votes
1answer
357 views
Understanding moments as forces?
I was watching this lecture on analysis of stress for mechanics of materials. At time 7:20, the lecturer says that in equilibrium, the sum of forces and "moments" in each direction (x,y,z) must be ...
0
votes
1answer
327 views
Calculating torque in a structure
I posted this on math stack exchange but realize it is more a physics question.
I have a structure which is set up as shown in the image. A weight hangs from point A with mass $m$. Joint B is free ...
2
votes
1answer
281 views
Why does the beam in a weighing balance get tilted proportional to the weights added to each pan?
I'm talking about a beam balance(a simple weighing balance with a beam and two pans hung on either side)
As answered in a previous question, the beam comes back to the original position when one ...
0
votes
3answers
189 views
How to imagine the following power and torque?
I can roughly feel a force of 10 newton only by considering the weight of 1 kilogram object.
How to imagine the following measurements?
Maximum horsepower 16 hp @ 9,500 RPM
Maximum torque ...
2
votes
1answer
417 views
Normal force in a compound pendulum (physical pundulum) system?
Consider a compound pendulum pivoted about a fixed horizontal axis, illustrated by the force diagram on the right:
#
Okay, I can't figure out where the normal force on the pendlum should point ...
0
votes
0answers
109 views
Load vs Leverage vs Friction on a floating pivot [closed]
If I had a standard 'cherry-picker' type of crane (lifting device), 7' high, with a 7' boom, suspending 1000# at its end,its vertical support mounted atop a 6" diameter ball-type pivot: how much force ...
0
votes
1answer
362 views
Can anyone solve this simple static equilibrium problem? [closed]
A bridge is 50m long, has a mass of 20,000kg, and rests on two pivots, A and B. The distance between A and the left side of the bridge is 10m. The distance between B and the right side of the bridge ...
4
votes
1answer
900 views
finding angular velocity and regular velocity when bouncing off a surface with friction
Take the game of pong as a simple example. When you hit the ball with a paddle that has a frictional surface, the ball will spin as well as change direction according to the coefficient of kinetic ...
0
votes
1answer
335 views
if a force is 1 newton metre, what is it at 2 meters?
If I have a force, say 24 kg/cm what would that equate to at 2cm? I would like to know the formulae for calculating this.
For example. If a motor can hold an object of 24kg at 1cm from its pivot ...
4
votes
3answers
2k views
Why are bicycle pedal threads' handedness left on the left and right on the right?
I understand the reason that bicycle pedals are oppositely threaded on either side. What I don't understand is why it works because I'm missing something.
Take the right pedal for example. It's ...
3
votes
5answers
499 views
How much force would be necessary to hold a 6-foot steel staff weighing 20 lbs from one end of it, parallel to the floor?
This isn't a homework problem. I'm asking cause I'm wondering how strong a person would have to be to pull it off. Their arms would be extended, both hands gripping the staff at one end, and the staff ...
