Newton's laws Definition and 478 Threads

A person pushes a 13.0 kg lawn mower at constant speed with a force of 84.0 N directed along the handle, which is at an angle of = 49.0° to the horizontal. (a) Calculate the horizontal retarding force on the mower (b) Calculate the normal force exerted vertically upward on the mower by...

I would like to review some principles, as well as pose some questions, to this highly intelligent community. As such, feedback of ideas, or comments, or even snotty remarks would be appreciated. Classical physics is built on Newton's laws. As such, Newton's laws always apply somewhere...

I am doing a bit of review and have discovered something I haven't thought about before. We all know Newton's third law (Fab)=-(Fba). So, how can there be acceleration? Say that Fab is 10N, then -Fba is -10N...10N - 10N = 0N. In an action reaction pair, if this net force is 0N...how can there be...

Hello all, I never really had a great deal of trouble with physics until just recently and this place looks like a great place to learn. I am having problems with the following question: A frictionless track is to be built as shown, with L=3.20 m and H=2.90 m. In order to get the cart to...

Newton's Laws-- 2 Questions-- Help Please Hey everyone I have two questions and any help on them would be greatly appreciated. Thanks a lot in advance. Problem #1 A person steps onto a dock off a boat that is tied securely and close to the dock. In another case, a person steps off a boat...

A1000N crate is being pushed across a level floor at a constant speed by a force of 300N at an angle of 20 degrees below the horizontal. (a) what is the coefficient of kinetic friction between the crate and the floor I was able to find this which is = .26 (b) If the 300N force is instead...

I have this homework problem that I really need help on. Thank you for your time Train A is traveling down a long straight track at a speed of 30m/s. The train A is 0.40km long and the last car at the very end of the train has a cannon mounted on it. Neglect the height of the cannon with...

Let's use the scenerio of a car going from uniform motion, to a turn to the left. I'm trying to describe this in relation to Newton's laws in hopes to get a greater understanding. What I know is that objects in the car are affected by Newton's first law, which states (among other things) that...

Hi. I have a physics question. I cannot get the right naswer. The question: Three boxes rest side-by-side on a smooth horizontal floor. Their masses are 1.10 kg, 3.45 kg, and 5.55 kg, with the 3.45 kg one in the center. A horizontal force of 20.0 N pushes on the 1.10 kg mass which...

I was wondering if anybody can help me out on this one.. I am doing a small project that requires me to: Write how Newtons laws relate to exercise, and give an example for each law.

A stone hangs by a fine thread from the ceiling and a section of the same thread dangles from the bottom of the stone. If a person gives a sharp pull on the dangling thread, the bottom string will break, but if he slowly pulls the bottom string the top string will break. After seeing this...

Hi everyone! I need some help. 1.)A .2 kg rock is thrown upward with an initial speed 15 m/s. What is the force on the ball in N when it reaches its maximum height? Would I use kinematics to find the max height then use F=ma? If so how? The answer is 2 2.) A woman whose mass as the...

An athlete whose mass is 93.0 is performing weight-lifting exercises. Starting from the rest position, he lifts, with constant acceleration, a barbell that weighs 500 . He lifts the barbell a distance of 0.700 in a time of 2.10 . Use Newton's laws to find the total force that his feet exert...

Q: A bag of cement of weight 339 N hangs from three wires as suggested in the figure below. Two of the wires make angles and with the horizontal. If the system is in equilibrium, find the tensions in the wires? The answer requires T1, T2, T3. I know T3 = Fgravity = 339N. I made a...

Here is the question I'm having trouble with: The average speed of a nitrogen molecule is about 6.70x10^2 m/s, and its mass is about 4.68x10^ -26 kg. (a) If it takes 4.20x10^ -13 s for a nitrogen molecule to hit a wall and rebound with the same speed but moving in an opposite direction...

A person stands on a bathroom (?) scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.75 of the person's regular weight. Calculate the elevator's acceleration, and find the direction of acceleration. The only thing that I really got is that the...

please help me check my answers, cause if i get one answer wrong, it's a big point deduction. i don't really like doing my homework online. here it goes... 1.) An object cannot remain at rest unless which of the following holds? A.)The net force acting on it is zero. B.) The net...

Is the gravitational force acting on a particle of mass m, on the surface of a sphere of radius 10^24 metres and with a mass of 10^52 kg given by G x10^52 m / (10^24 ) ^ 1/2 - the Newtonian value - or is the mass density high enough for general relativity to be required to get a sensible...

Hello fellow scientists! I wanted to know if anyone could prove Newtons laws to for me. I remember a friend did once but i wasnt paying attention at the time. What i remember was him telling me that F=ma could be broken down into a more complex equation with partial darivatives to solve more...

Here is an answer I have just given to a question about the journey of light, which applying its logic you can derive QM and GR. Newton's first law of motion state "Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it."...

A horizontal force of 100N pushes a 12kg block up a frictionless incline that makes an angle of 25 degree with the horizontal. a) what is the normal force that the incline exerts on the block? b) what is the acceleration of the block? ----------------------------------------------------...

The problem was pretty simple i thought, but according to the book i get the wrong answer. I think i might be approching the problem wrong. "In the drawing, the weight of the block on the table(block1) is 422N and that of the hanging block(block2) is 185N. Ignoring all frictional effects and...

Newton's laws? there is an athlete climbing a rope in gym class. he gets to a point halfway up the rope and is stationary. someone puts a bag of sand that is equal in weight to the athlete. they are both static and then the athlete starts to climb the rope, slowing and speeding up at random...

Right well there is this question which I am stuck on and could do with some help with! Thanks! A runner decelerates as he runs into a windy exposed area, from a speed of 4 m/s to 2 m/s in 8 seconds. His mass is 60 kg. Assuming he also experiences a frictional force of 3 N, find the size of...

Okay, in my class we've been learning basic problems solved by applying Newton's laws. I understand the general idea, but I get confused with problems like the first one. How would I solve it taking both forces on it into account? On the second problem, I don't know how to solve it because it...

Which one of Newton's laws is this equation from and why? a=[(m1-m2)g]/[m1+m2]

Hi, we're starting our chapter on Newton's Laws and force and I wanted to know if I am approaching the following problem correctly: A car travels 53 km/h and hits a bridge abutment (what's that?). The person in the car moves forward 65 cm (w/respect to the road) while being brought to rest by...

If anyone could help me with these problems, I'd be eternally grateful ... 1) The distance between two telephone poles is 51.0 m. When a 0.800 kg bird lands on the telephone wire midway between the poles, the wire sags 0.210 m. How much tension does the bird produce in the wire? Ignore the...