# What is Accceleration: Definition and 48 Discussions

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2. ### Why did I get two different results for the mass m2?

I wonder why did I get two different answers for m2 using two different approaches? The correct answer is m1=3kg, m2=7kg. So pleases if someone can take a look. Also can someone suggest how am I supposed to find the force that dynamometer is showing? I was thinking that it equals (m1+m2)*g...
3. ### Why body A has greater acceleration?

Apparently body A has greater acceleration and I don't get why. Can someone please explain. It's stated to take g=10/s^2. Both bodies have same mass. Nothing about rope elasticity is added, and nothing about the pulley. So I assumed they are both massless, and no friction between them. Also...
4. ### I Is an accelerating frame the same as an inertial frame at a point?

If we have an observer that is accelerating in one direction (perhaps a rocket ship accelerating towards the sun), would its reference frame be identical to an observer at the same point that is not accelerating, but has the same instantaneous velocity? In other words, is an accelerating...
5. ### Solving a Puzzling Physics Problem: ##15 \pm 3\sqrt{15}##

So this isn't actually a homework question, it's a question that was on the test I just took and I cannot figure out what I'm doing wrong. I've tried solving it three or four different ways, double checking everything, and I keep getting ##15 + 3\sqrt {15}## or ~26.6, which was not one of the...
6. ### Acceleration of the cart on a Ferris Wheel (Circular Motion)

After 3,32 seconds, vt should have varied by 0,695*3,32. I have done a previous exercise where you only needed to calculate the radial acceleration in this scenario. There, I took the vt after the given time, squared it and then divided with the radius. I remember clearing that one, so in this...
7. ### A Motorcycle, the force exerted upon from collision

Synopsis, The insurance company wants to repair this 3-year-old motorcycle with 3400 miles on the odo father taking this hit. The motorcycle was modified with an aftermarket "engine guard," which was made out of powder-coated steel tubing and bolted directly to the frame which is made out of...
8. ### Two forces acting on an object given in vectors - SOLVED

I tried splitting the forces up into F1 and F2 making Newtons second law equation into F1+F2=ma. Then I added over the the first force given. multiply the mass to the acceleration terms to get F2= (m*ai + m*aj) - F1
9. ### Solving Motion Equations with Integration

I'm not sure where to start, when I tired using integration of the initial equation to get pos(t)=-.65t^2 i + .13t^2 j + 14ti +13tj but after separating each component, i and j, and setting j equal to zero I got 0 or -100 seconds which doesn't seem like a reasonable answer.
10. ### Acceleration-Time Graph and Velocity Multiple Choice Question

The variation with time t of the acceleration a of an object is shown What is the change in velocity of the object from ##t=0## to ##t=6##? A. ##6ms^{-1}## B. ##8ms^{-1}## C. ##10ms^{-1}## D. ##14ms^{-1}## So apparently the answer is B, which I am having trouble reconciling. Using methods...

12. ### Average acceleration of an arrow by a bow

Distance= (Intial Velocity + Final Velocity / 2) Time 0.75 = (0+75 / 2) Time 0.75 = (37.5) Time 0.02 seconds = Time Acceleration = (Final Velocity + Intial Velocity) / Time Acceleration = (75 - 0) / 0.02 Acceleration = 3750 m/s2 Idk if this is correct can someone help pls.
13. ### Why does acceleration increase by less as angle of slope increases?

My only guess is that this is due to air resistance. Below an example of the predicted graph:
14. ### Mechanics: Two masses on a pulley causing two cylinders to accelerate

Hi! I need help with this problem. m1-2-3-4 and R are given. There is no slip in the system. I have to give F1-2-3-4 in respect of the masses and R. Here is what I managed to m1 is easy: m1*a = m1*g - T(tension of the rope) m2: m2*a = T - (?) <-- I have a problem with this. F1 and F3 is the...

16. ### Calculate the speed of a point based on a graph

Homework Statement A point moves rectilinearly in one direction. The figure shows the distance s traveled by the point as a function of time. Using the graph, find: The average speed of the point during the movement time. Maximum speed The moment t0 in which the instantaneous speed is equal to...
17. ### Inertial force acceleration (vertical axis)

Hi, How is the inertial force Fi (acceleration) when the system is vertical. I noted Fi_horizontal=m.a, Ff=mg.μ.cos(Θ) et Fg=mg.sin(Θ) .
18. ### Minimum deceleration to prevent a collision

Homework Statement At a given time ##t=0##, a car 1 moving with constant velocity ##v_{1}## breaks with constant deceleration ##d##. Another car 2 at a distance ##L## behind car 1 and traveling with constant acceleration ##a_{2}## and velocity ##v_{2}## at ##t=0## brakes immediately as soon as...
19. ### Acceleration of a particle on a parabola

Homework Statement A particle moves along a parabola on the x-y plane with equation ##y^{2}=2px## with constant speed ##1000m/s##.What is the magnitude of its acceleration? Homework Equations Parametric equations ##\vec{r}=(b^{2}t^{2}/(2p),bt)##. The Attempt at a Solution...
20. ### Rotational Mechanics Homework: Equations & Solution for Part 1 Work

Homework Statement Homework Equations E=T+U T=1/2 mv^2 U=∫F⋅dr The Attempt at a Solution Part 1 Work x=x-dot y=y-dot z= z-dot r=r-dot θ=θ-dot [/B] T= 0.5m(x^2 +y^2) 0.5M(z)^2 Changing to polar coordinates T=0.5m(r^2 +rθ^2) 0.5M(z)^2 U=-Mgz E=T+U =0.5m(r^2 +rθ^2) 0.5M(z)^2-Mgz z=L-r...
21. ### Circular motion — the acceleration is not constant?

Homework Statement An object moves at constant speed in a circular path. True statements about the motion include which of the following? a) the velocity is constant b) the acceleration is constant c) the net force on the obj is 0 since its speed is constant Homework Equations hm none...
22. ### Finding Initial Velocity v0x for Particle with Non-Constant Acceleration

Homework Statement Find the initial velocity v0x such that the particle will have the same x-coordinate at time t= 4.07 s as it had at t=0. The acceleration of a particle is given by ax(t)=−2.00 m/s2 +( 3.09 m/s3 )t. Homework Equations v = v0 + a t Δx = ((v+v0)/2)t Δx = v0t + 1/2at^2 v^2 =...
23. ### I Which object will hit the surface of a planet first?

If we have two objects A and B appear on the opposite sides of the equator of a planet like Earth with the same mass as Earth. Object A is a neutron star with the mass of the sun and object B is a iron cube with the mass of one gram. Will A or B hit the Earth at the same time or will one hit...
24. ### I Dropped objects hitting the ground at the same time?

okay, so I’ve had this random thought. We have all been told that objects fall to the ground at the same speed, even if they have different masses. While it’s true that any two objects, regardless of mass, will accelerate towards Earth at the same speed, that doesn’t mean the Earth is...
25. ### B How absurd are these numbers really?

I stumbled upon these numbers on my test recently. It is raelly basic stuff, but i want to know, what would actually happen if such thing happened in the real world. We basically have a ball made of 20Kg of "person". And it it accelerates at 1.8*10^5 m/s² for 1/30 of a second reaching 6000 m/s...
26. ### Displacement given the acceleration

Homework Statement How could I get the distance traveled by a vehicle having only its constant acceleration as data? Homework Equations I know that the acceleration is the derivative of the velocity and the velocity is the derivative of the position. The Attempt at a Solution I don't know how...
27. ### Relationship between Velocity and Acceleration

When the driver applies brakes its velocity starts decreasing and direction of acceleration will be same to the direction of velocity. Is this statement True of False? Please explain the true concept of this scenario. As far as I understand is that Velocity will start decreasing. But I am...
28. ### B How to calculate travel time as a function of distance

I need help calculating travel time as a function of distance using drag equation: F_drag = crossection area * density * ballistic coefficient * 0.5 * v^2. Not posted in homework cause it's not, and I don't know how to solve integrals so I could not fill solution attempt box
29. ### Change in Momentum of a Hockey Puck

Homework Statement A hockey player hits a slap shot, exerting a constant force on a 3.06 kg puck for 0.06 seconds. What is the change in momentum of the puck? Homework Equations Impulse = Mass x (Change in velocity) = Force x time (I think that’s all needed? Most likely missing one.) The...
30. ### How to find coefficient of friction *Without* mass?

A car traveling at 97 km/h can stop in 48 m on a level road a.) Determine the acceleration of the car b.) Determine the coefficient of friction between the tires and the road Homework Equations : Vf^2=Vo^2 +2aΔx μ=Ff/mg[/B] 3. I have part A, I got -7.53 m/s^2, but I can't seem to...
31. J

### What if the actual force for a Newton was different?

ince f=ma, and we derive whatever the force it takes to accelerate a specific mass at a specific acceleration as a unit of force. I understand this ratio of actual force will always be the same in the entire universe but is there a reason why for example 1kg accelerated a 1m/s^2=1 N which is...
32. ### Change in direction of velocity

If I'm driving a car and I have changed my dierction of motion without changing the speed, in this case how to calculate the acceleration of the car in a particular time? I'm not talking about circular motion.
33. ### Auto-Closing Gate (Relative Acceleration problem homework)

1. Homework Statement It's an auto closing gate. Two parts of the gate are identical. I had given to find the time taken to close the gate. The distance to close point (P) of the gate from closed event of the gate is given as "a". Sorry for my bad English. What i need to know is how the two...
34. ### Object moving on a spiral figure

Homework Statement We've got an object/person in the center of a cicrcle that spins around with an angular velocity ω. That same object is moving at a constant speed k with the direction of the radius, that is from the center to the outside of the sphere. That object describes then a spiral...
35. S

### Constant acceleration changes direction twice

Hello, I just did a practice physics problem that asked if an object with constant acceleration can change direction twice. The answer was no. What if you had an object attached to a string spinning at constant velocity. Is the tangential acceleration constant?
36. S

### When simple motion begins is there acceleration and jerk

Ive been looking at the simple physics problems for 2D motion. For example, a ball starts from rest and is thrown at 5m/s at an angle of 30 degrees with respect to the ground on earth. Most of the problems assume that the acceleration in the x-direction is 0. Doesnt there need to be an initial...
37. ### How to calculate the maximum RPM of a motor?

Hello all, Just wondering if there is a mathematical formula that calculates the maximum rpm. If I have a fan that puts out 3 pounds of rotational force at stall speed(completely still) at the end point of a 1.5 ft blade what would be the maximum rpm of this fan with the blade attached. What...
38. ### Initial Velocity of a dropped object problem

Why we take initial velocity of dropped object downwards as 0 and 25m/s when the object is thrown 25m/s upwards ? What is then initial velocity cause when t=0 both object dropping and moving upwards had 0 velocity - in other words when object came to motion at both places it had some velocity?
39. ### Finding Velocity: F=ma or KE = 0.5mv^2

Here is a made up function of force changing with respect to displacement: F(x) = 2000 - 100x The force is applied onto an object, pushing it horizontally. Ignore friction and air resistance. The mass is constant. I'm trying to find Velocity with respect to displacement. Attempt 1: Knowing F =...
40. ### Is true force just "accepted" if it satisfies Newton law?

So I understand the relationship between mass x acceleration=force but all that relationship tells me is "Whatever the force is to accelerate a given mass at a specific unit of acceleration = units of force, and we just accept whatever the unit of force is. example 1/ms² x 1 kg mass = 1 N...
41. ### Distance an object travels after sliding and falling from roof

Homework Statement [/B] My physics teacher - "You may like this question, its very structured" Calculate the distance a slate tile falls from a roof The roof is angled at an angle 30 degrees. mass of slate tile is 0.8kg The length of the roof is L=6m The height of the roof above the ground is...
42. ### Acceleration Vector Word Problem

Homework Statement Famous quarterback Fleet O. Floote is attempting a quarterback draw by running up the middle toward his goal line at 4.6 m/s. A linebacker hits him squarely, and their combined final velocity is 3.8 m/s at an angle of +120.° from the quarterback's original direction. The time...
43. ### Finding the magnitude of acceleration in 2D motion

Homework Statement A car moving due south at 20.0 m/s enters a highway cloverleaf. The car will exit the cloverleaf to merge with westbound traffic traveling at 29.0 m/s. The time between entering the cloverleaf and exiting to merge with westbound traffic is 20.7 s. What is the magnitude of...
44. ### Angular Acceleration and relative velocity

Homework Statement In the mechanism shown below, the angular velocity of link 2 is 17 rad/s CW, constant. Find the angular velocity (magnitude and direction) of link 3. The distance between A and C is 109 mm, the length of link 3 is 125 mm, and θ= 111°. Note: B is a pin-slider In the...
45. ### Angular acceleration of Pendulum equation

Is this a legitimate equation? θ'' = − g⁄R sin θ Source: ftp://www.myphysicslab.com/pendulum1.html ftp://www.myphysicslab.com/images/pendulum_2.gif The pendulum is modeled as a point mass at the end of a massless rod. We define the following variables: θ = angle of pendulum (0=vertical) R =...
46. ### Braking speed and distance traveled

Homework Statement The acceleration of a particular car during braking has magnitude bt, where t is the time in seconds from the instant the car begins braking, and b = 2.2 m/s3 .If the car has an initial speed of 60 m/s , how far does it travel before it stops?Homework Equations : [/B] I know...
47. ### Will the Tractor and Tesla Avoid a Collision on the Mountain Road?

Homework Statement Problem 5: Collision course A huge tractor and a Tesla full of school children come driving along a winding mountain road, in opposite directions. The tractor has a speed of 40.0km/h and the car zooms along with 80.0 km/h. The Tesla suddenly comes around a corner, sees the...
48. ### Accceleration due to gravity of a Black Hole

Homework Statement The radius Rh and mass M of a black hole are related by Rh = \frac{2GM}{c2}, where c is the speed of light. Assume that the gravitational acceleration ag of an object at a distance ro = (1 + ε)Rh from the center of a black hole is given by ag = \frac{GM}{r2}, where ε is a...