All Questions
47 questions
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Clarification on Momentum vs Inertia in Exerting Force when Stopping
I encountered a physics question in an exam four years ago that I believe may have had an incorrect answer key. I'm seeking clarification on the correct concept.
The question was:
The property of ...
2
votes
4
answers
183
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Does it take more energy to bring a car to a halt if it is still accelerating on impact than travelling at constant speed?
So, my physics is quite rusty, been out of varsity for a while.
A friend asked me this and I am still pondering. Here is the scenario:
2 Cars are travelling towards a wall, and make impact with the ...
- 29
1
vote
0
answers
79
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What is happening on an atomic level (or lower) when a object is in motion (inertia)?
If you have an iron ball and throw it upwards you are imparting a force which opposes gravity.
Initially this force is easily understood by your hand pushing the ball upwards, so the atoms in your ...
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4
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254
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How can you figure out when inertia or momentum is keeping the object in motion?
If we consider the case of Earth, inertia carries the Earth forward (inertia alone will make the Earth go out of orbit so gravity keeps it in orbit around the sun), but if we consider the case of a ...
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2
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125
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Are there two competing definitions of "inertia"?
The term inertia is often introduced by stating Newton's first law: An object stays at rest or moves with $\vec{v}=const.$, if the resultant force is zero. This feature of masses is called "...
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2
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Why is a larger force needed when you decrease the distance in regards of torque? [closed]
I think it's because of inertia.
- 107
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3
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354
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Why don't we use momentum to quantify inertia?
My understanding of Newton's 1st and 2nd laws have led me to believe that inertia and momentum are the same.
1st law: An external force is required to overcome an object's inertia
2nd law: Force is ...
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1
answer
217
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Inertia of an elevator
Imagine a situation where we have a relatively light empty elevator moving up at a pretty high constant velocity say something above $10\ m/s$, just so that it has a considerable amount of momentum ...
2
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4
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909
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Is there any relation between inertia and momentum?
Inertia is the that property of an object because of which that object resists a change in its state of rest or motion.
Momentum of an object is the product of mass and velocity, or its the quantity ...
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1
answer
101
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If you could zero out your momentum, could you travel faster than the speed of light [closed]
I figure I'm going to get ridiculed for this question, and maybe deservedly so. The sensor images and eyewitness accounts from the Naval Aviators released last year of unexplained aerial phenomena ...
- 207
2
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3
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563
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Are there any explanations for Inertia at atomic level? [closed]
At macroscopic level we can observe inertia. But what explanations are there for Inertia at molecular/atomic/quantum level?
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3
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208
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What would happen if an astronaut tried to swing a baseball bat in free fall?
I am interested in finding out how swinging a baseball bat or similar object would affect the astronaut's rotation in free fall, on the ISS for instance. How much would the astronaut swing the bat, ...
0
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2
answers
249
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What factors influence the energy loss in a bounce?
Suppose a spherocylindrical solid is let to fall from some height to a flat, solid surface, bouncing some height up after it reaches the surface. The object clearly loses some of its energy due to the ...
0
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2
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344
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Physics of pushing the top of a box a little bit to make it rock back and forth
Context:
I'm trying to make a simulation of a box that you can apply force to the top and it will oscillate back and forth until the energy in the system reaches equilibrium again.
Visual ...
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0
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2
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38
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Is there a way to find out how long a body will glide after a force is applied once? [closed]
Can you tell how long a body will retain it's motion after being given a push from x amount of force (ex. 15 force applied, motion will last 18 seconds)?
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4
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Do photons have inertia?
We all know the example where we say that a massless box containing photons has inertia, because the photons exert pressure of the inner walls of the box.
But my question is about a single photon ...
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1
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How do you apply each of Newton's laws to specific scenarios?
The 3 Newton's laws of motion are easy to be understood but examples citing which law caused it are so confusing - say a bullet fired from a gun - many people state it cause is 3rd Law - but I see all ...
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6
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How can energy have inertia?
How can energy have inertia?
To my intuition, inertia is so closely associated with mass that my intuition says "Huh?"
Indirectly by mass energy equivalence it works fine, for example:
I have a ...
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0
votes
1
answer
33
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An expanding, sliding charged tube's self-imposed electromagnetic induction
If I have a simple cylindrical electrically-insulating tube possessing a net electrostatic charge and allow the tube to slide parallel to the tube's axis, that tube will possess electric currents ...
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0
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2
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414
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Can momentum be considered as a measure of inertia of motion?
If inertia of motion is a body's tendency to be in motion then can momentum be considered as a measure to calculate that tendency to be in motion?
1
vote
1
answer
200
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Convert inertia formula to excel calculator
I've been looking at this question:
"Weight" of moving object in a car collision
but to be honest I can't get my head around how to work it out myself (I'm not a physics student!). What ...
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6
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0
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3k
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Does "Quantized Inertia Theory" violate conservation of momentum? [closed]
This recent news article reports that DARPA is doing work with "quantized inertia", despite their claim that it's not widely accepted by physicists:
The Defense Advanced Research Projects Agency (...
- 267
1
vote
1
answer
452
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Is Newton's third law due to inertia?
Newton's third law states that each force has an equal and opposite force. If I kicked a ball, it would apply the same force on me. Is this due to the ball's inertia? To clarify, is the ball exerting ...
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1
answer
192
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Is the inertia of light equal to the inertia of mass under $E=mc^2$?
Under $E=mc^2$, 1kg of matter has $9\times 10^{10}$ joules of energy. So, if I had just the light shining from $9\times 10^8 $ 100 Watt light bulbs inside a perfectly reflective box, would that light ...
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0
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1
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284
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Calculating New Velocity Vector of Moving Object [closed]
A 1kg object is moving through space. A force is applied to the object of 1N perpendicular to the direction of travel for 1 second.
Assuming there are no other external forces on this object, (...
0
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2
answers
657
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Does horizontal inertia affect the time it takes something to reach the ground?
I am new to physics.
I’m confused about how an bullet shot horizontally would land at the same time with as a bullet dropped vertically (ignoring air resistance and the curvature of Earth).
Having ...
user76860
-1
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1
answer
417
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Using a gyroscope to get to space
Theoretically, if you could get an inertial mass or gyroscope spinning fast enough while on the earth' s surface, then as the earth turned would it continue to travel in a straight line and therefore ...
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2
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165
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How to measure propulsive efficiency of a human powered boat? [closed]
I am asking for help to measure the effective propulsive force and its effect on boat glide on a human powered vessel using a paddle.
Senario
A person using a paddle to propel a boat or canoe. ...
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0
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1
answer
1k
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Inertia of a Car?
I was reading through my driver's manual, when I came across this picture:
I don't think the inertia arrow is accurate: inertia/momentum would be pointing directly forwards, while centripetal force ...
- 111
2
votes
5
answers
1k
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Would you be able to get off of a frictionless surface?
Imagine that you are standing (naked) in the center of a level circular disk (with a radius of, say, 3 meters) that is completely frictionless.
Without resorting to blowing air or excreting any ...
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2
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1k
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Does Inertia really define the resistant ability of a body
I was reading the chapter Newton's 1st law of Motion , where I met the definition of Inertia.
The property of an Object by virtue of which it neither changes its state nor tends to change the state,...
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2
answers
2k
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A bullet makes a hole but a rock shatters the glass
Consider a bullet fired toward a pane of glass. Barring slight cracks, it creates a relatively clean hole in the glass. On the other hand, when a stone is projected toward the same glass pane, it is ...
user106570
3
votes
2
answers
1k
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Does a wave have inertia?
In de Broglie hypothesis, particles have wave nature. The question is does this wave have inertia? If so is it represented in the corresponding wave equation?
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1
vote
1
answer
105
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What is the minimal G-force curve in 2-dimensional space?
Given two parallel roads, which need to be connected, what shape of curve would produce the minimum overall horizontal G-force(s) on travelers?
Is it a $sin$ or $cos$ wave?
Is it a basic cubic ...
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1
answer
1k
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How to compensate a top-heavy platform [closed]
I have a small four-wheeled platform weighing 1.3kg with a height of 30cm. Its center-of-mass is located at 75% of the height, making it a little top-heavy.
I empirically measured the angle at which ...
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4
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3
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2k
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Does the Inertia of a Cue Ball Affect its Reflection Angle off a Resting Billiard Ball?
Consider the following Diagram in which a Cue Ball (A) of mass M is shot twice at another pool ball with identical mass M.
When the force with which the cue ball (A) is hit (v1) is increased (v2) it ...
1
vote
1
answer
3k
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What causes the skidding of the wheels of a moving car? Momentum or inertia?
In a moving car, when brakes are applied suddenly the wheels skid.I have these two explanations in my mind and both seems correct to me.1. The momentum of the car must be conserved so the car ...
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0
votes
1
answer
1k
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How do momentum get transferred?
Simple Question ,
Consider two objects namely $A$ and $B$ where $B$ is stationary and $A$ is moving towards $B$ with velocity $v$.
When the two objects touch each other what does actually happen ...
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30
votes
9
answers
102k
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Inertia Vs Momentum
At my recent lesson on kinematics, my teacher taught about inertia and momentum. This is what she said.
Inertia: a characteristic of an object that resists changes to its state of motion.
Momentum: ...
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5
votes
7
answers
10k
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Can we explain Newton's first law mathematically?
At constant speed there is no acceleration. $(f'(x)=v'=0=a)$ .If $a=0$ then $F=ma=0$ and therefore no force acts on the object so the object will continue in the same direction, if any. This is only ...
- 1,053
2
votes
2
answers
3k
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Will I be able to push a small object in front of me in the outer space?
Imagine I am standing on Earth, and pushing a tennis ball away from me. The ball moves. If it is very heavy, I will move back instead of the ball. Now consider the same scenario in outer space, where ...
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3
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2k
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Inertia and momentum
Question #1: Why does speed have nothing to do with inertia?
Question #2: If a car hits a steel wall and stops, where did the momentum go?
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2
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1
answer
98
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Work done or not in this case?
I have a very simple question. A motorboat directed upstream is seen to be at rest from the bank of a river. Is the engine doing any work? Is it right to say that since it is not causing any ...
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vote
1
answer
292
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Why won't this reactionless drive idea work (motor with a moving weight in space)
I know people will say it violates many laws of motion and conservation but could anyone explain why it is so?
It's NOT a question about free energy.
Imagine a motor in space. It has an arm (rod) ...
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0
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1
answer
399
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Perceived sway difference between double-decked vs. single-decked buses?
Why is that when I'm standing in a moving double deck bus, my body doesn't move a lot; whereas, in a moving single deck bus, my body moves quite a bit? It seems like I swing a lot in single deck buses,...
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2
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2
answers
1k
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Does trade affect Earth's rotation? [duplicate]
Every country is trading with other countries around the world, some more than others. I was wondering if there would be any change to the Earth's rotation because of the imbalance of trade between ...
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8
votes
2
answers
785
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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 ...
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