Newton 2nd law Definition and 143 Threads

Homework Statement This is the problem from the book "physics for scientists and engineers..." by Serway, Jewett / Chapter 5, problem 98 Initially, the system of objects shown in Figure P5.93 - is held motionless. The pulley and all surfaces and wheels are frictionless. Let the force F be...

Homework Statement I have a double incline mass problem where Φ=43° and θ=20°, mass_A=1.00kg and they are connected by a massless string where the net force of each block is equal to 0. Homework Equations I believe I am to use Newton's 2nd law to find the force of the tension which I have next...

Homework Statement a car moving to the left with constent accelration. a ball is hanging from the ceiling held in 90 degrees to the ceiling until t=0, then it is realesed and start to swing. find the max angle. Homework Equations Newton's second law The Attempt at a Solution...

Homework Statement Acceleration experienced by an astronaut in a rotating space station. Homework Equations What force would he experience is his own rotating frame of reference. The Attempt at a Solution Newton's second Law for a rotating frame is: mr'' = F net+ Fcor + Fcf Fnet (In the...

I am interested in having a dialogue with persons familiar with MOND (modified Newtonian Dynamics as proposed by Israeli physicist Mordehai Milgrom). Also, how MOND fits with Erik Vanderlinde's theory of Emergent Gravity. I am an engineer by training, but enjoy physics as a hobby. Specifically...

Homework Statement Part a of the image below. When I try to solve this question, I can't get the solution in the answer key. In the answer key the y component of the normal force is NCos(alpha) in the last line. Does the normal force not point perpendicular to the ramp? Homework Equations...

Hi Everybody! Lets say I have a sphere or an elipsoid of 10m3 full of air so it floats. I then open a valve that let's water in. At some point it will start to sink to the bottom. Let's say 100m deep. Once its down there I would like to refloat it. Which should be the most efficient method...

Homework Statement A mass of 3kg is acted upon by three forces of 4.0 N, 6.0N, and 9.0N and is in equilibrium. The 9N force is suddenly removed. Determine the acceleration of the mass. Homework Equations F=ma. The Attempt at a Solution My main problem with this question is that I cannot think...

Homework Statement A rectangular board laying on the ground of mass ##M## is pulled with a force ##F## to the right, while a cylinder of mass ##m##, radius ##R## rolls without slipping on the board. Assume there is no friction between the board and the floor. Which way does the cylinder roll...

Homework Statement A uniform cylindrical wheel of mass ##m_{1}## and radius ##R_{1}## rotates with angular velocity ##\omega_{1}##. It lies a certain distance (along the same axis) from a static wheel of radius ##R_{2}## and mass ##m_{2}##. The wheels are then pushed against each other with a...

Homework Statement Looking for F for 200 km/hr Homework Equations F=ma The Attempt at a Solution F-cv^2 = ma F= ma +cv^2 v=200 km/hr F= ma +c(200 km/hr)^2 so now I need to find a, from previous work I found that t= (m/c)*(1/2 vter)*(ln[ (vter +v)/(vter-v)]) next I would solve for v...

Homework Statement [/B] A child sits on a sled (50kg) on a snowy hill with an incline of 5 degrees. The coefficient of static friction is 0.05. What downward force must a parent apply parallel to the normal force, to prevent the child from sliding down the hill? (Answer: 366N)Homework Equations...

<Moderator's note: Moved from a technical forum and thus no template.> Is what I have done correct ? I want to find v(t) from Sigma F = m*a. I have gravity force mg pointing downward with positive direction and resistive force R = -b*v^2 pointing upwards with negative direction are acting on a...

Problem: https://drive.google.com/open?id=19PDuyshgP6u4U9mXU3BfrF031J8wL12B Attempt: I tried to solve the range by listing out the Newton's 2nd laws of each drum https://drive.google.com/open?id=1Eslg2Wy3orG41eywwm_O6qN4OQ3QN-bA and from the equations of the drum 2, I get...

Homework Statement Two blocks m1 and m2 are connected by a weightless rod are on a inclined plane of ∅=37° and μ =0.25 .What is the common acceleration and Tension of rod if m1 is 4 kg and m2 is 2 kg such that the 4kg block is the upper block. OPTIONS A =4m/2 T=0 B =2m/2 T=5N C =10m/2 T=10N D...

Hello, Let us imagine a solid in a free fall on planet Earth and let us neglect the effect of air resistance on the motion of the solid. According to Newton's Second Law of Motion, since the only force being applied on the solid is its Weight, then its acceleration must be its Weight divided by...

Homework Statement A light rod ##AB## of length ##2a## has a particle ##P## of mass ##m## attached to ##B##. The rod is rotating in a vertical plane about a fixed smooth horizontal axis through ##A##. Given that the greatest tension in the rod is ##\frac {9mg}{8}##, find, to the nearest degree...

Homework Statement [/B] There are two blocks that have equal mass m, they are connected by a spring (with a coefficient of elasticity k) that has length l0. Instantly on the left block a force F begins to act. What will be the min. and max. length of this spring during this movement. There...

Homework Statement A block of mass M is at rest on an incline that makes angle theta with the horizontal. Given that the static coefficient of friction is mu_s1 and the kinetic coefficient friction mu_k, what is the magnitude of the force of static friction exerted on the block by the incline...

Homework Statement In an empty container, having the shape of a Rectangular Parallelepiped, with width l=0.5m and MN=H=0.4m, and NP=L=0.75M. we poureda mass of mercury =2448kg. T0,T1,T2 have the same section which is 0.2 m^2. we give g=10N/kg, and density of mercury u=13.6 g/(cm^3)...

In the derivation of F=ma, when we reach the point F=kma, we take k=1. Why can't we take 'k' as some other value? I will be thankful for help!

Homework Statement A uniform chain of mass 'm' and length 'l' rests on a rough incline (inclination is angle 'Q') with its part hanging vertically. The chain (inclined) starts moving up the incline (and the vertical part moving down) provided the hanging (vertical) part equals to 'n' times...

Homework Statement The question is in the attached document Homework Equations Newton's second law states that F=ma Charged particle in magnetic field experiences F=Q ( v X B) The Attempt at a Solution Since the charge 'Q' is constrained to move along a path in xy-plane in such a way that the...

Homework Statement Two crates, A and B, are in an elevator as shown. The mass of crate A is greater than the mass of crate B. a. The elevator moves downward at constant speed. ... iii. Rank the forces on the crate according to magnitude, from largest to smallest. Explain your reasoning...

Homework Statement A force F is applied horizontally to a block A of mass mA = 0.600 kg so that it slides on the floor with acceleration g/3. Block B of mass mB = 0.200 kg rests on top of A, but is kept in place by a cord which is tied to the wall at 45.0°. The coefficient of kinetic friction...

The situation: The mass is pushed up an incline with an angle of 1 degree with an initial velocity of 1 m/s, and it comes back down to its original position. The questions to answer: What is the total distance the object travels on the frictionless inclined plane? How long will the object...

Homework Statement Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m .FInd the time...

Hi there, I am new here so please don't be too hard on me yet and move this post if i placed it in the wrong forum. I am developing a little experiment game and i want the train to drive using real physics, but I am really bad at physics. So my question is is how do I calculate the friction of...

Homework Statement [/B] A block travels in the positive x-direction with some velocity ##v_0##. It is subject to a drag force $$F(v)=-F_0e^{Kv},$$ where ##F_0,\,K## are positive constants. Find the point in time when the velocity of the block momentarily goes to zero. Find how far the block has...

Homework Statement A proton is initially located at the origin of some coordinate system (at rest), when a time-dependent force, $$F(t)=F_0\sin{(\omega t)},$$ is applied to it, where ##F_0## and ##\omega## are constants. a) Find the velocity and displacement of the proton as functions of...

Hi! I want to start solving problems from the text 'Orbital Mechanics for Engineering students' by Curtis 2nd edition. Is this the right place to post? Homework Statement 2.1 Two particles of identical mass m are acted on only by the gravitational force of one upon the other. If the distance d...

At high school, we saw without demonstration the fundamental principle of dynamics (2th Newton's law), i.e : $$\sum \vec{F}=m \vec{a}\,\,\,\,\,\,\,\,\,eq(1)$$ after, at university, we saw another expression of this 2th Newton's law : $$\sum \vec{F}= \dfrac{d\vec{p}}{dt}\,\,\,\,\...

Homework Statement A spring with spring constant k is attached to a box of mass M in which is placed a small body of mass m. The system is displaced a distance A from equilibrium and released from rest. Find the normal force between the box and the small mass as a function of time. For what...

I found a problem and I'm having one question, it goes like this: A box of 5 kg is being dragged across the floor with a horizontal force of 40 N. If it starts at rest and it begins to accelerate at 3 m/s2 (constant acceleration), find: A) The coefficient of kinetic friction B) Supposing that...

Two small blocks, each of mass m, are connected by a string of constant length 4h and negligible mass. Block A is placed on a very rough tabletop as shown below, and block B hangs over the edge of the table. The tabletop is a distance 2h above the floor. Block A is then released from rest at a...

So I was curious about something. Having a flat tire today and having to change my tire made me wonder. I understand torque and force are 2 different things though related they have separate meanings. So my question is if I have a 2 foot tire iron and I am torquing my nuts. Let's say they...

Hello, I was referring to this thread: https://www.physicsforums.com/threads/accelerating-atwoods-machine-problem.44305/ to solve a problem on accelerating atwood machines in which, naturally, one attempts to find the acceleration of each of the individual masses. Although I now understand how...

Homework Statement In a physics laboratory the value of g , the gravitational acceleration in the vicinity of Earth, has been measured accurately by projecting a ball up an evacuated tube and electronically timing the passage of the ball in its upward and downward flight through two light...

Homework Statement A projectile launched at A with an initial velocity of 24 m/s at the angle θ=60deg, impacts the vertical wall at B. Neglecting air resistance, calculate the height h Homework EquationsThe Attempt at a Solution Here is my solution As you can see to find height h I assumed...

Homework Statement A 2000-kg is launched vertically from the surface of the earth. The engine shuts off after providing a constant propulsive force of 60 kN for the first 20 seconds. Neglect the reduction in the mass of the rocket due to the burning of the fuel and the variation of the...

Homework Statement The cart carrying the small 9-N package A is moving up the incline with constant acceleration α. If the package stays at rest relative to the cart in the position θ=45deg, determine the value of α. Neglect friction. Homework EquationsThe Attempt at a Solution [/B] Are my...

I know that the force of gravity is (ma)=GMm/r^2 or a=GM/r^2 This makes sense and If I were to drop a bowling ball down to Earth I'd expect it to fall with 9.8m/s^2. However I can calculate that the bowling ball has its own gravity using the formula noted above. My question is what will be the...

Hi, While solving homework problems, I start by defining a positive-y direction and a positive-x direction. Let's say up and to the right. Until now, I've applied this same rule to all objects in each problem, no matter the direction the object moves. But it seems I have not understood this...

I don't understand the motion of an accelerating wedge and a block. I'd really appreciate if you make me understand the motion in both an inertial and a non inertial reference frame. Here's a figure I have made, a0 is the acceleration on the wedge with respect to an inertial frame, towards right.

Homework Statement Problem: A 12.0-kg block is pushed to the left across a rough horizontal surface by a force that is angled 30.0◦ below the horizontal. The magnitude of the force is 75.0 N and the acceleration of the block as it is pushed is 3.20 m/s^2 . What angle does the force exerted on...

Based on my current understanding of the problem I do not see this following derivation as valid, although this is what was given in my course notes. Although this particular example is from an undergraduate physics course this is not a homework problem: I'm confused about the underlying...

<Mentor's note: moved from a technical forum, therefore no template> My teacher made this question: Iceman is sliding down a 10.0 x 10^(-8) nm ice that is inclined at 20.0 degrees with respect to the horizontal. Iceman is initially at rest. The coefficient of kinetic friction between iceman's...

Homework Statement A 0.140kg baseball traveling 35.0 m/s strikes the catcher's mitt, which in bringing the ball to rest, recoils backward 11.0cm. What is the average force applied by the ball on the glove Homework Equations F=ma; FAB=-FBA The Attempt at a Solution Not sure where to start for...

Homework Statement An 8.5 gram slug is fired East from a 0.357 magnum hand gun held 1.5 meters above the ground. The muzzle velocity (as the projectile leaves the gun) is 1400 ft/sec. The bullet is accelerated at a constant rate as it travels through the 10 cm long barrel. After leaving the...

I would like to know what gear ratio i would need for my electric longboard. The goal is to run the longboard at 30 - 40 km/h at max power. Me and the longboards weight is approximately 65 kg. The brushless motor i am running has an rpm of approximately 18000 rpm (as it is an airplane engine)...