Motion sickness
You are riding in a car, trying to take a nap with your eyes closed, when all of a sudden you feel yourself pushed against the side of the car. At that moment, the car must be
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8 solutions
you should be pushed back! to the side means turning.
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Yes, I know that there's some ambiguity in the wording of the given problem but since I have to choose from those 4 options and "turning" is not one of those options, so I have to assume that the car was following a linear path and not a curved path.
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But while travelling in a closed circular path, the body is still said to be accelerating.......I don't think that the question had any ambiguity
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@Varenya Srivastava – Correct! Even if we assume it's travelling in a circular path, we can still say that it is accelerating. So, the correct answer remains the same in both of the conditions. :)
Yes you are right the question was doubtful.
I too think the same.
What is the difference between accelerating and speeding up
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When a ˉ . v ˉ > 0 , object "speeds up". Acceleration may even change the direction and no magnitude or even decrease the speed!
You are correct
Exactly.. @Yeo Chiaw Soong
If you are accelerating, you should be pushed back. pushing against side of the car happens only when turning.
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The phrase "pushed against the side of the car" is a little ambiguous for some people, maybe! But, since none of the 4 choices suggests "turning", so we have to consider that the car follows a linear path and "pushed against the side of the car" refers to being pushed towards the backside of the car!
but speeding up is also the same thing!
I think the picture is not illustrating the problem (driver seat belt)
@prasun biswas ..... whats wrong with "speeding up" ? It will also affect the inertia
How against the side of of car?
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We consider here that "against the side of the car" here interprets as "towards the car seat"! We have to assume that the car was following a linear path of motion because none of the options for the answer suggests "turning of the vehicle".
In general, if we consider that the car maybe follows a linear or a curved path, then both the answers "Turning" and "Accelerating" would have been true due to inertia of direction and inertia of rest and motion respectively. But since none of the options for the answer suggests "turning of the vehicle", so we have to assume that the car was in a linear path! The phrase "pushed against the side of the car" in the question is a little ambiguous, considering the answer that was set by the problem sharer! I think it should have been "pushed towards the backside of the car" so as to avoid any ambiguity!
Please remember the definition of ACCELERATION. " The rate of change of VELOCITY". Velocity is a VECTOR quantity, i.e involving both speed & direction, (a) going in a constant direction & changing speed is acceleration,or (b) going at constant speed & changing direction or, (c) both a+b.
In this case the being thrown sideways basically indicates a constant turn where the centrifugal force is throwing you against the outer side of the turn. This acceleration can be calculated.
In a linear path you are bot thrown sideways. You either get pushed in the seat,being slower then the car (step on accelerator) or you are thrown out of seat (braking) if you are facing in the direction of motion or other way if you are facing the other way which is common in vehicles. You can be thrown sideways if you are sitting facing sideways I.e perpendicular to the direction of motion.
you get pushed to the side only on corners due to centrifugal force. Dont post in incorrect or ambiguous language please. :)
speeding up means accelerating in the forward direction which means decelerating in the backward direction. more than 1 answer is given.
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the only reasonable answer is therefore accelerating sideways (due to centripetal accn when car travels in an arc) which is the only way u feel u r turning sideways
This is problem of pseudo\fictious force which is always opposite to the direction of acceleration
even if the car was turning it can be included in accelarating because it was changing its direction
wrong... the car accelerating will push you into your seat - Towards the rear of the car - NOT to the side. To be pushed to the SIDE the car would have to be turning, centrifugal/centripetal forces pushing you into the side - so "traveling at a constant speed" SHOULD be the correct answer.
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They explained this in another comment, it's considering the back of the car as the "backside" of the car
When the vehicle is changing direction it is said to be accelerated
Why cant we say that it was making a turn and hence was in circular motion with uniform velocity??
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this question is certainly ill framed.But in these type of questions you have to choose the best possible answer. since no other option other than acceleration is giving any information about changing direction,so i think it should be the best possible answer. also the answer could also be slowing down(with change in direction).
Velocity is a vector, which means it requires a direction. The car may have uniform speed , but if it is changing direction, it automatically changes velocity .
They must have meant pushed back. To the side means a change in direction. Must be the same people who write bad cookbooks.
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Velocity is a vector, which means it requires a direction. The car may have uniform speed , but if it is changing direction, it automatically changes velocity .
If the option change in direction was included then the question might have become to naive the question (with the options) was perfect.The car was accelerating because of the change in direction and not because of increase/decrease in speed.
this is new thing which I came to know today.
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As the velocity depends on direction s it may change with the change in direction; and when the velocity changes it accelerates.
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Then slow down or decelerates is also a possible ans.
That is true, but instead of confining yourself to the rate of change of speed, push both things in. In flying this acceleration is calculated in terms of "g's" where 1 g= 32 ft/sec/sec or 9.8 meters/sec/sec.
True .. It has been explained in different words by almost every one.
Why is it accelerating and not speeding up...aren't they the same thing
In physics, the technical definition of acceleration is a change in velocity. Velocity is made up of two components: speed and direction (a vector quantity). Given this definition, acceleration can happen in three ways: a change in speed, a change in direction, or both. So in this question, accelerating is the correct answer because there was clearly a change in direction.
You are right.
If we define this simply, in terms of inertia... while the car is accelerating in a straight direction you will find yourselves being pushed backwards against the seat of your car and you tend to experience a sideways push only when the car is turning. Thus, arises a problem of change in direction and resulting in the change in the velocity vector, but instead of creating a problem it is solving it. As, in any instance while a car turns it changes it's direction and assuming that the speed is constant (i.e. uniform), velocity being a vector quantity will definitely change. Therefore, the body (car) will accelerate, since, acceleration is defined as the change in velocity. So, the correct answer is indeed 'acceleration'.
We can think like a pseudo force is applied on our body. As motion is relative concept, when car accelerated for us, it would also mean that we accelerated for car, and if a body having mass is accelerated demands that the force is applied, it is though not a real force, its just relative to car and us.
Upon reading the statement "pushed against the side of the car", you can actually infer that the car is moving along a circular path (unless you haven't experienced riding a car swerving along a curve). In circular motion, velocity is always changing because it should be tangential to the circular path (its direction changes). However, its magnitude (thus, speed) remains the same. This eliminates two of the choices. The correct answer would be "accelerating" since there is centripetal acceleration exerted by the car to keep its circular track.
I will just rephrase your answer. When the wheels have been turned, produces centripetal force causing the car to turn. The desire of the car to get out of the turn (go tangentially) is the centrifugal force..
I think that the motion of the car is curved or in other words, the car is moving in a curved path. So that moment when you fell yourself suddenly pushed against the side of the car was NOT caused by INERTIA but by CENTRIPETAL FORCE . Since Centripetal Force is directed towards the center of the curved or circular path , it is possible that a person inside the car to be "pushed" against the side of the car.
Velocity is a vector quantity so it is composed of a magnitude and a direction. Since the car is travelling in a curved path, direction always change therefore velocity is never constant. Therefore the choice "travelling in a constant velocity" is wrong .
Acceleration is also a vector quantity and also composed of a magnitude and a direction. If the car speeds up or slows down, it changes its speed and its acceleration. But the car does not necessarily change its direction. It means that the car is moving in a linear motion does applying Newton's First Law of Motion or the Law of Inertia, your body must move opposite to the direction of acceleration (forward or backward). Therefore the choices "speeding up" and "slows down" are wrong .
Again acceleration is a vector quantity. In a curved path, direction always change. Since direction changes, acceleration also changes therefore by the concept of Centripetal Force, explained earlier, the choice "accelerating" is correct .
Following the law of inertia, your body tends to be in the state in which it is currently.It is clear that since you were suddenly pushed, it means that the velocity was changed. Now, we know that change in velocity is known as acceleration.Acceleration either means 1) Change in speed or 2)Change in direction(as velocity consists of direction). You were pushed to the side , which means that the car must be turning. Hence the answers will be" accelerating"
This problem is based on inertia . When the velocity of the car was constant, your body was also adjusted to that velocity (as if you are at rest , with the car considered as a reference frame ) but when the car accelerated suddenly, the car's velocity changes but the body tends to remain at the previous velocity due to inertia and so you feel yourself pushing against the side of car .
So, the car must be accelerating at that moment.