Tagged Questions
0
votes
3answers
268 views
A man running on the treadmill
Imagine a man is running on a treadmill. His inertia with respect to floor will be zero because he is not moving with respect to floor. If both he and the tread mill suddenly stops he will not fall, ...
0
votes
3answers
100 views
Why is $F = mg - T$ in this case?
The situation is as follows:
I am told that $F_{net} = mg - T$ in this case, but doesn't that not take into account that $T$ isn't applied to the center of mass? Newton's second law is defined for ...
1
vote
1answer
255 views
Kinetic Energy And Rotational Motion
The problem is, "A metal can containing condensed mushroom soup has mass 220 g, height 11.0 cm and diameter 6.38 cm. It is placed at rest on its side at the top of a 3.00-m-long incline that is at ...
0
votes
1answer
291 views
Finding Rotational Kinetic Energy Of A Clock
The problem I am working on is:
"Big Ben, the Parliament tower clock in London, has an hour hand 2.70 m long with a mass of 300 kg, and a minute hand 4.20 m long with a mass of 100 kg (see figure ...
0
votes
2answers
2k views
Tensions And Pulleys With Masses
The problem I am working on is:
"A block of mass m1 = 1.80 kg and a block of mass m2 = 6.30 kg are connected by a massless string over a pulley in the shape of a solid disk having radius R = 0.250 m ...
0
votes
2answers
469 views
Torque And Moment Of Inertia
I am reading the two concepts mentioned in the title. According to the definition of torque and moment of inertia, it would appear that if I pushed on a door, with the axis of rotation centered about ...
0
votes
1answer
919 views
Calculating Moment Of Inertia
The problem I am working on is:
A uniform, thin, solid door has height 2.10 m, width 0.835 m, and mass 24.0 kg.
(a) Find its moment of inertia for rotation on its hinges.
(b) Is any ...
0
votes
1answer
136 views
Two Different Sorts of Inertia: Inertial Mass and Moment of Inertia
There are two different sorts of inertia: inertial mass and moment of inertia.
I am currently reading about moment of inertia. Now, I know inertia is an important concept; with it, we can determine ...
0
votes
0answers
166 views
Why Is Linear Inertia Only A Property? [closed]
The Inertia of a body is said to be its property or virtue that is directly proportional to its mass. Now if we consider Inertia of rectilinear motion, it depends on the mass as well as the ...
1
vote
2answers
997 views
Why does a ball bounce?
If an object is acted on by equal and opposite forces then it will be in equilibrium, and it's acceleration or velocity (and so direction as well) will not be changed.
So when a ball bounces, it ...
2
votes
3answers
307 views
The two faces of $F = m*a$
As I have understood,
$F(t)=m \cdot a(t)$
can have 2 different meanings:
When applying an external force $F$ on a point mass of mass $m$, the resulting acceleration of that mass at time $t$ is ...
4
votes
2answers
279 views
Would a sneeze by a cosmonaut in a spacesuit affect his movement?
Naive question; feel free to shoot me down
It is a truism that any motion in space would continue indefinitely unless it is opposed by an external force. If a cosmonaut were to sneeze within his/her ...
4
votes
3answers
419 views
Infinite acceleration?
Why is acceleration regulated by mass? In a frictionless environment, why doesn't an object move at infinite acceleration if force is applied on it?
Force causes movement, so unless there is an ...
1
vote
2answers
408 views
Moment of inertia of a coin
I have a a coin infinitely thin, rotating along the diameter.
How to derive the formula for it's moment of inertia passing through the diameter.
I was suggested to use the surface density and ...
2
votes
1answer
97 views
Pushing, inertia of a cart system
I have a cart with another cart on top which gets pulled down by another cart on the side. There is no friction.
The question is:
How strongly do I have to push with $F$ to keep the cart $m_1$ ...
20
votes
4answers
3k views
How does a mobile phone vibrate without any external force?
How does a mobile phone vibrate without any external force? By Newton's law, any body can't move without any external force
