Tagged Questions
-3
votes
0answers
14 views
Length Traveled from Complete Stop [closed]
A one-meter long rifle fires a bullet at a velocity of 800 m/s. What is the average acceleration experienced by the bullet when it is fired? (Hint: You need to find the time it takes the bullet to ...
-1
votes
1answer
35 views
If An Object Explodes With A Force, What Force Are Fragments Given?
So let's say for example I have an object with 5kg of mass.
It explodes with a force of 500N.
The object fragments into four fragments: a 0.5kg, a 1kg, a 1.5kg and a 2kg object.
What force does ...
1
vote
0answers
49 views
Does the slinky base stay perfectly level during the initial free fall [duplicate]
In this related question:
Slinky base does not immediately fall due to gravity
It is observed that the base does not fall immediately.
Obviously the center of mass is in free fall, and the tension ...
1
vote
2answers
50 views
Clarification regarding Newton's Third Law of Motion and why movement is possible [duplicate]
Newton's third law states that to every action, there is an equal and opposite reaction.
If that's the case, then how do things move at all? Shouldn't all applied forces be canceled by the equal and ...
-2
votes
1answer
53 views
Why is there no such thing as a body in a state of acceleration?
It appears that velocity is a quantity of motion meaning that all objects can have assigned to them a particular velocity. Through the application of forces (ex: gravity, E&m) we measure changes ...
0
votes
0answers
13 views
Determining the acceleration of one to another with three unknowns [closed]
Given the following image, how would you determine the acceleration of block A, and the acceleration of block B relative to A? I'm trying to include the pulley as part of block A but I cannot figure ...
0
votes
1answer
66 views
Change in speed of a satellite
Suppose there's some satellite orbiting the earth in circular motion. Suppose there's an asteroid that hits the satellite in the same direction as the instant velocity vector of the satellite. The ...
7
votes
1answer
251 views
Is acceleration an average?
Background
I'm new to physics and math. I stopped studying both of them in high-school, and I wish I hadn't. I'm pursuing study in both topics for personal interest. Today, I'm learning about ...
3
votes
2answers
161 views
Nonuniform acceleration due to rubber rope
What I want:
I have a rubber rope which is $5m$ in length when not stressed and is able to stretch about $100\%$ (to $10m$ long). I want to accelerate a constant mass horizontally, which has ...
4
votes
1answer
82 views
How did Newton find out force has something to do with acceleration?
Its about Newton's second law of motion,
$$F=ma.$$
It says the acceleration of an object is directly proportional to the net force and is inversely proportional to the object's mass. Yes I can ...
0
votes
1answer
79 views
Kinematics with non constant acceleration
A particle experiences an acceleration described by
$$
a=kx^{-2}
$$
where x is the displacement from the origin and k is an arbitrary constant.
To what value does the velocity v of the particle ...
1
vote
2answers
93 views
Accelerating an elevator
A person is standing on a weighing scale in an elevator in upward acceleration.
Let $N$ be normal reaction force exerted by the weighing scale to the person (upward).
It is known that the person ...
0
votes
3answers
114 views
Force with zero acceleration [duplicate]
If I apply a force on a body which is kept against a wall, then the body will not move. The body is not moving means that its velocity is zero, and hence its acceleration is also zero. According to ...
1
vote
1answer
112 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 ...
2
votes
2answers
97 views
Where are we : On level ground or on a ramp - moving in a train?
Let's say we are traveling in a train. The path has two parts: one at ground-level and the other moving up on the ramp. The ramp has an inclination of $\arctan\frac{a}{g}$ with the horizontal, where ...
2
votes
2answers
83 views
Will we feel right up inside the airplane if the airplane accelerates toward earth at 20m/s^2?
Suppose you are in the airplane and the airplane falls toward the earth with acceleration of $20m/s^2$(double of gravitational acceleration $g$). This double acceleration by airplane will cancel the ...
5
votes
1answer
113 views
Slinky base does not immediately fall due to gravity
Why does the base of this slinky not fall immediately to gravity. My guess is tension in the springs is a force > mass*gravity but even then it is dumbfounding.
-1
votes
1answer
93 views
New to physics and need some help with understanding acceleration [closed]
The free fall acceleration of an object under earth's gravity is directed toward?
When the same amount of force is applied to two different masses, the smaller mass will be accelerated ____ than the ...
2
votes
2answers
149 views
Fictitious forces confusion
I have a hard time understanding the subject of fictitious forces. Let's discuss a few examples:
1) I'm sitting inside a vehicle which is accelerating in a straight line. I feel like someone is ...
2
votes
2answers
216 views
Small car colliding with large truck
A small car collides with a large truck. Why do both vehicles experience the same magnitude of force? Wouldn't the large vehicle experience less force than the small one?
5
votes
2answers
123 views
In mechanics, is shock really better expressed as jerk instead of acceleration?
Some expensive electronics or mechanical devices are designed to be shock-resistant. However, the manufacturers often market the level of shock-resistance in units of g-force (I know g-force is really ...
3
votes
1answer
170 views
What does it mean to find acceleration in terms of g?
I'm having trouble understanding what a problem I have is seeking.
To simplify the problem:
A particle reaches a speed of 1.6 m/s in a 5.0 micrometer launch. The speed is reduced to zero in 1.0 ...
0
votes
1answer
134 views
Basic classical mechanics question
A and B are in a lift. The mass of the lift is 250kg. As it moves upward, the floor of the lift exerts a force of 678N and 452N on A and B, respectively. The tension in the cable of the lift is 3955N.
...
5
votes
4answers
460 views
Why do we weigh less when falling?
I don't want to go to science world to find out because it would be a long round-trip.
I understand that acceleration/deceleration would effect the weight and I can also imagine that someone at ...
6
votes
8answers
479 views
Can you completely explain acceleration to me?
I understand what acceleration is, and I know the formula, and I understand it's a vector.
I just don't understand how the equation works exactly. I'm kind of picky, I know, but bear with me.
...
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 ...
2
votes
0answers
30 views
One dimensional motion with changing acceleration. Falling to a large body from a great distance [duplicate]
Possible Duplicate:
Radial fall in a Newtonian gravitational field
My math and physics are rusty. I am trying to calculate the time an object takes to fall to a large body. Before you ...
0
votes
2answers
259 views
Linear motion with variable acceleration
Consider the following problem
I pull a mass m resting at x = 0 on a frictionless table connected to a spring with some k by an amount A and let it go. What will be its speed at x=0?
I know how to ...
2
votes
4answers
876 views
Physics behind Wheel Slipping
Lets say that I'm in a car and I apply full acceleration suddenly. Now, the wheels would slip and hence the car doesn't displace much.
But If I start with some constant acceleration, slipping doesn't ...
1
vote
1answer
138 views
Is $w=mg$ the right way to calculate mass?
How can you find the mass of an object by using a weight and a gravitational acceleration from another planet then earth? I was given $5.8\text{ N}$ and an acceleration of $4.0\ \mathrm{m/s^2}$. The ...
0
votes
2answers
278 views
Center of gravity of vehicle and vehicle performance
I am interested to know how does CG of vehicle plays role in the Fuel economy and the vehicle performance. Does CG of vehicle has anything to do while accelerating of your vehicle. I am a student, ...
-1
votes
4answers
203 views
How to send a spacecraft to the moon without any acceleration
I have two (maybe equal) question
1- Is this possible to send a spacecraft to the moon without any acceleration(Constant speed)?
2-Is this possible to throw a ball on the top of tree without any ...
3
votes
2answers
606 views
How can an object's instantaneous speed be zero and it's instantaneous acceleration be nonzero?
I'm studying for my upcoming physics course and ran across this concept - I'd love an explanation.
2
votes
5answers
962 views
Why Gravity attracts all objects with the same speed?
Why Gravity attracts all objects with the same speed? Is this question was solved? What is the exact answer?
0
votes
3answers
915 views
Why is force described as rate of change of momentum?
momentum = mass * velocity
Differentiating both sides leads to
force = mass * acceleration
since the mass doesn't participate in the differentiation as it is constant.
Is this a sound ...
0
votes
2answers
2k views
Why does a parachute decrease terminal velocity?
Terminal Velocity depends on two things- surface area and speed. These are inversely proportionate.
If both these variables affect terminal velocity, why do parachutes slow you down? Initially you ...
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 ...
0
votes
1answer
158 views
Deceleration of Vehicle off pavement
How would I calculate the deceleration of a vehicle (ATV), wheels locked, on dirt? How long would it take to halt? How fast is it decelerating?
I used this calculator, but it seems incorrect for a ...
1
vote
1answer
773 views
Can we determine the force an object exerts by its mass and acceleration?
I understand that the objects acceleration is determined by the force exerted on it, and that the force exerted on it is determined by its acceleration.
But, does an object's (named A) acceleration ...
0
votes
2answers
1k views
What is the force exerted on a body that doesn't move?
If I push against a brick wall I'm exerting a force against the brick wall the the brick wall will exert the same force against me. These will cancel each other out and neither myself or the wall will ...
0
votes
3answers
652 views
Who is right? Force exerted on a body. Me or my friend?
Three masses $m_1 = 3\text{ kg}$, $m_2 = 9\text{ kg}$ and $m_3 = 6\text{ kg}$ hang from three identical springs in a motionless elevator. The elevator is moving downward with a velocity of $v = ...
1
vote
2answers
213 views
Using acceleration to plot position
Sorry if this question is dumb, and I know is physics 101, but I'm not that good with physics.
I'm writing an iPhone program that by collecting the acceleration data of the device tries to replicate ...
0
votes
0answers
306 views
Two objects with masses Question help [closed]
I got this wrong on a test. Can someone explain how to get the answers? I provided the answers. I just need an explanation.
Two objects with masses of 3.10 kg and 6.90 kg are connected by a light ...
3
votes
5answers
558 views
Confused about the role of mass
I'm far from being a physics expert and figured this would be a good place to ask a beginner question that has been confusing me for some time.
According to Galileo, two bodies of different masses, ...
4
votes
4answers
700 views
Is acceleration an absolute quantity?
I would like to know if acceleration is an absolute quantity, and if so why?
