Tagged Questions
-3
votes
0answers
23 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 ...
6
votes
4answers
129 views
Integrating radial free fall in Newtonian gravity
I thought this would be a simple question, but I'm having trouble figuring it out. Not a homework assignment btw. I am a physics student and am just genuinely interested in physics problems involving ...
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 ...
-1
votes
1answer
87 views
Acceleration, velocity and speed
It is given that acceleration is constant, so can we infer that average speed and velocity are the same?? Moreover, circular motion is out of the question, as the function of x(t) where ...
-2
votes
0answers
28 views
Acceleration of a particle [closed]
A particle move along a straight line such that distance x traversed in t seconds is given by $x= t \times 2(t+1)$ , the acceleration of a particle, will be
A) $3t^3-2t$
B) $3t^3+2t$
C) ...
3
votes
2answers
162 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 ...
0
votes
0answers
23 views
Motion of a particle when acceleration depends on position [closed]
I´m given an acceleration vector in parabolic coordinates which depends on the position
a=F(u,v)u+G(u,v)v
Having all the initial values of the problem, how do i solve for the equations of motion.
I ...
2
votes
1answer
98 views
Need help with the position of a particle in a velocity-versus-time graph
I am having trouble with a velocity-versus-time graph. I recently took a Physics test that asked this question: The graph shows the velocity versus time for a particle moving along the $x$ axis. The ...
0
votes
1answer
84 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 ...
3
votes
2answers
67 views
Sign of acceleration
I'm developing an application using accelerometer sensor. I'm not good at physics so forgive me if the question is trivial. If I have 3 values of acceleration: $x$, $y$, $z$, I find acceleration ...
0
votes
2answers
184 views
What's the acceleration of pendulum when velocity is zero
For a pendulum which has a light string to hang a bob, I know that when the bob swing to the leftmost or rightmost end, the velocity of the bob is zero and the acceleration should be maximized. But if ...
0
votes
0answers
62 views
An unmarked police car passed by a speeding car [closed]
Hi I'm trying to solve the problem
An unmarked police car traveling at a constant speed of 95 km/h is passed by a speeder traveling at 140 km/h. Precisely, 1.00 s after the speeder passes, the ...
1
vote
1answer
118 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 ...
0
votes
1answer
70 views
Kinematics question [closed]
An electric train accelerates uniformly from rest to a speed of 20m/s which it maintains until the brakes are applied. It is then brought to rest by a uniform retardation equal in magnitude to twice ...
2
votes
2answers
98 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 ...
0
votes
2answers
121 views
How can I add an acceleration vector to a velocity with a different direction?
I am in my last year of high school and am struggling with some homework. I'm sorry if this question is incredibly stupid, but I simply can't find the answer in my notes.
If I have an object with a ...
-1
votes
2answers
49 views
In space, which would accelerate faster, the space station or an astronaut? [closed]
In space, which would accelerate faster, the space station or an astronaut?
My answer: Both the same, ( no or little gravational friction) but, depending on iniitial force that started the motion.
...
-1
votes
1answer
95 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 ...
0
votes
0answers
54 views
At an acceleration of 2ft/s^2, how fast could I reach 9.8MPH? [closed]
Question title is self explanatory.
If I'm accelerating at $2ft/s ^{2}$, how long does it take to reach $9.8MPH$?
0
votes
0answers
79 views
Physics about plane take off simple find the acceleration problem [closed]
This was on my test, but I kinda botched it I think.
I was trying to use
V^2f = Vo^2 + 2a(delta x)
A plane must reach 226km/h to take off. Runway is 2000m. What's minimum acceleration needed? ...
0
votes
1answer
74 views
Vertical velocity to reach a certain point given a flat horizontal velocity? [closed]
Suppose I have two points such as $a(4,6,9)$ and $b(32,5,12)$.
If I have a flat velocity pointing $a$ to $b (b - a)$ which has an arbitrarily defined magnitude. Given gravity $g$,how can I calculate ...
3
votes
1answer
179 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 ...
2
votes
1answer
159 views
Why can we say there is no tangential acceleration in this specific problem?
I'm looking at a problem involving a simplified rollercoaster with only 3 cars (connected with weightless rods) for which the friction and distance from the carts to the rails can be ignored. The part ...
0
votes
1answer
137 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.
...
0
votes
1answer
83 views
exercise concerning the inclined plane
I have an exercise to ask yourself.
A ball of mass m = 5 g starts at rest and travels 50 cm along a ramp
inclined at 45 ° to the horizontal. a) If we imagine frictionless motion
of the ball along the ...
0
votes
2answers
109 views
Negative sign of acceleration [closed]
This is the problem from our Physics textbook :
A player throws a ball upwards with an initial speed of 29.4 m s–1.
(a) Choose the x = 0 m and t = 0 s to be the location and time of the ball at ...
0
votes
2answers
262 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
1answer
410 views
Calculate acceleration and time given initial speed, final speed, and travelling distance? [closed]
A motorcycle is known to accelerate from rest to 190km/h in 402m.
Considering the rate of acceleration is constant, how should I go about calculating the acceleration rate and the time it took the ...
0
votes
0answers
74 views
How do I figure out the normal force on a person on an accelerating platform? [closed]
My question is an elaboration on this question: Force on rope with accelerating mass on pulley
The elaboration is to determine what the Force that the platform exerts on the person. Assume the ...
0
votes
3answers
558 views
Calculating car's acceleration from change in angle of hanging object?
The question essentially is based on a situation like this-
A car has a small object hung from the cieling on a string (apparently at an angle of 0 degrees to the ceiling).
The car is accelerating ...
0
votes
0answers
530 views
What is the tension in the string? [closed]
A light string pulls a $8.0 \space kg$ object directly upward with an acceleration of $2.45\space m/s^2$. What is the tension in the string?
1
vote
1answer
139 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 ...
5
votes
2answers
285 views
relativistic acceleration equation
A Starship is going to accelerate from 0 to some final four-velocity, but it cannot accelerate faster than $g_M$, otherwise it will crush the astronauts.
what is the appropiate equation to constraint ...
0
votes
1answer
2k views
Finding deceleration and velocity using distance and time
A car is moving down a street with no brakes or gas. The car is slowing due to wind resistance and the effect of friction. The road is flat and straight. The only data I have are timings taken at 100m ...
1
vote
0answers
89 views
maximum distance between accelerating objects started at different times [closed]
Let there be two objects that have zero relative velocity with respect to each other in an inertial frame. If they both undergo identical accelerations, but one starts the acceleration at t = T1 and ...
0
votes
3answers
363 views
Finding instantaneous speed in MPH given acceleration, RPM and gear ratio
I am still trying to figure out how to (semi) accurately model instantaneous speed after having found acceleration. I have found that at higher RPMs, the resultant acceleration will be lower. I was ...
2
votes
2answers
846 views
Finding acceleration for a car after finding torque
I am trying to calculate the acceleration of a vehicle after finding the torque $\tau$. Assuming my Horse Power is 130 and my RPM is 1000, I calculated torque as:
$$\tau = \frac{130 \times ...
0
votes
2answers
260 views
Does acceleration at an angle to velocity change the direction?
During an interval of time, a tennis ball is moved so that the angle between the velocity and the acceleration of the ball is kept at a constant 120º. Which statement is true about the tennis ball ...
2
votes
3answers
586 views
Example in the book: A simple accelerometer
A simple accelerometer
You tape one end of a piece of string to the ceiling light of your car and hang a key with mass m to the other end (Figure 5.7). A protractor taped to the light allows you ...
1
vote
2answers
74 views
Acceleration: Value Disparity?
If we consider a ball moving at an acceleration of $5ms^{-2}$, over a time of 4 seconds, the distance covered by the ball in the first second is $5m$. In the 2nd second will $5 + 5 = 10m$. In the ...
0
votes
3answers
654 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
0answers
184 views
How to model an accelerometer measurements on a car wheel?
I am working on kinematically modelling an accelerometer on a car wheel.
When working on the initial conditions, I am confused whether or not I should use the gravitational acceleration since there ...
1
vote
2answers
530 views
Calculating the gravitational acceleration inside of a planet
Plant X has a radius of 5000 km and is composed of two layers.
The first inner layer ranges from the centre to 2000 km from centre, it's density is 8 kg / dm^3.
The second layer ranges from 2000 ...
2
votes
1answer
421 views
Force on rope with accelerating mass on pulley
I have a pretty basic pulley problem where I lack the right start.
A child sits on a seat which is held by a rope going to a cable roll (attached to a tree) and back into the kid's hands.
When it ...
0
votes
0answers
308 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 ...
2
votes
3answers
2k views
Convert acceleration as a function of position to acceleration as a function of time?
Suppose I have acceleration defined as a function of position, "a(x)". How to convert it into a function of time "a(t)"? Please give an example for the case a(x)= x/s²
0
votes
2answers
3k views
Not sure of a homework solution involving average acceleration
A 50.0 g Super Ball traveling at 25.0 m/s bounces off a brick wall and rebounds at 22.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 3.50 ms, what is the ...
1
vote
2answers
246 views
What method should I use to solve for the final acceleration of a projectile being launched from the earth's surface?
What method should I use to solve for the final acceleration of a projectile being launched from the earth's surface?
The question I am working on is:
A projectile is launched vertically from ...
1
vote
3answers
4k views
Find radius of curvature, given a velocity vector and acceleration magnitude?
The particle P moves along a space curve. At one instant it has velocity $v = (4i-2j-k)$ $m/s$. The magnitude of the acceleration is 8 $m/s^2$. The angle between the acceleration and the velocity ...
0
votes
3answers
242 views
Deccelerate and Accelerate to achieve timed journey
I have a vehicle traveling at initial speed $100\:\mathrm{m/s}$.
Expected destination speed is also $100\:\mathrm{m/s}$.
Maximum deceleration is $3$.
Maximum acceleration is $10$.
Distance to the ...
