What is Kinematics: Definition and 1000 Discussions
Kinematics is a subfield of physics, developed in classical mechanics, that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the forces that cause them to move. Kinematics, as a field of study, is often referred to as the "geometry of motion" and is occasionally seen as a branch of mathematics. A kinematics problem begins by describing the geometry of the system and declaring the initial conditions of any known values of position, velocity and/or acceleration of points within the system. Then, using arguments from geometry, the position, velocity and acceleration of any unknown parts of the system can be determined. The study of how forces act on bodies falls within kinetics, not kinematics. For further details, see analytical dynamics.
Kinematics is used in astrophysics to describe the motion of celestial bodies and collections of such bodies. In mechanical engineering, robotics, and biomechanics kinematics is used to describe the motion of systems composed of joined parts (multi-link systems) such as an engine, a robotic arm or the human skeleton.
Geometric transformations, also called rigid transformations, are used to describe the movement of components in a mechanical system, simplifying the derivation of the equations of motion. They are also central to dynamic analysis.
Kinematic analysis is the process of measuring the kinematic quantities used to describe motion. In engineering, for instance, kinematic analysis may be used to find the range of movement for a given mechanism and working in reverse, using kinematic synthesis to design a mechanism for a desired range of motion. In addition, kinematics applies algebraic geometry to the study of the mechanical advantage of a mechanical system or mechanism.
Grade 11 Physics Final Project. Help! (Kinematics)
first of all, I am new to the forum. and i was wondering if i should post this on homework forum or general physics. then i decided to post it here.
so i have been working on a final project for my grade 11 physics.
the teacher wants us...
Homework Statement
A motorcyclist accelerates rapidly so the bike entirely rests on the back wheel, while the midpoint of the back wheel O' accelerates with constant acceleration a_o' horizontally.
The entire bike rotatoes with angular velocity \frac{d}{dt} \theta and angular acceleration...
Homework Statement [/B]
Hey guys, so here is my question:
A huntsman fires a gun pointing at a monkey hanging on the branch of a tree. The huntsman and the base of the tree are on a flat horizontal. At the moment the huntsman fires the gun, the monkey will release it's grip on the branch of...
Homework Statement
Two cars start from rest and travel in opposite directions.
Car A travels at 6m/s^2 to a maximum of 30m/s. Car B travels 5m/s^2 to maximum of 35m/s. 200m between them. When will they meet?
Homework Equations
d=vt
d=vit + 1/2 at2
The Attempt at a Solution
at 6...
Homework Statement
Consider a system of two masses joined by a massless string with the string passing over a massless frictionless pulley with a radius of
5.0 cm.
The mass of the left is
9.00 kg
and the mass on the right is
1.60 kg.
Find the angular acceleration of the pulley when the...
Homework Statement
I am stumped on a problem (number 13 page 49) from the Serway/Vuille/Faughn text
College Physics 8th Ed. The problem is
A person takes a trip driving with a constant speed of 88.5 km/h, except for a 22 min rest stop.
If the person's average speed is 77.8 km/h, how...
Homework Statement
You're driving down the highway late one night at 18m/s when a deer steps onto the road 41m in front of you. Your reaction time before stepping on the brakes is 0.5s and the maximum deceleration of your car is 12 m/s/s
Homework Equations
1) How much distance is...
Question: "A man steps from the top of a tall building. He falls freely from rest to the ground, a distance of h. He falls a distance of h/4 in the last 0.800 s of his fall. Neglecting air resistance, calculate the height h of the building.
I've attempted the solution in a number of different...
Homework Statement
A cat spots a flowerpot that sails first up and then down past an open window. The pot is in view for a total of .50s and the top-to-bottom height of the window is 2.00m. How high above the window does the flower pot go?
I was trying to help one of my friends with...
Homework Statement
A proton (charge +1e and mass 1.67e-27kg) and an alpha particle (charge +2e and mass 6.64e-27kg) are placed 3 fm (1 fm=10e-15m) apart.
a)what is the force on each particle
B)what is the potential energy of the system?
c)what is the acceleration of each particle at the...
Homework Statement
A rocket is launched straight up with constant acceleration. Four seconds after liftoff, a bolt falls off the rocket. The bolt hits the ground 8 seconds later. Three seconds after the bolt falls off, the rocket's engines fail. How high does the rocket go before it begins...
1. Problem
The kicker stands 50 m from the goalpost that is 3 m high. She kicks with an initial velocity of 24.5 m/s. She just makes the goal height-wise, but did the ball travel far enough? She kicked at an angle of 35.28 degrees.
2. Homework Equations
S = (1/2)at^2 + V0t + S0
S =V0xt...
Homework Statement
A weather rocket is launched straight upwards. The motor provides a constant acceleration for
18s, then the motor stops. The rocket altitude after 26s after launch is 5800m. What was the rocket's acceleration during the first 18 seconds?
Homework Equations
[ tex ]x =...
Homework Statement
You're driving down the highway late one night at 18m/s when a deer steps onto the road 45m in front of you. Your reaction time before stepping on the brakes is 0.50s and the maximum deceleration of your car is 12m/s^2.
a)How much distance is between you and the deer when...
On a test today I came across a rather ridiculous question, in which I chose the incorrect answer. The problem is, based on my understanding of kinematics I am unsure as to why I got it wrong.1. The question stated: Miley Cyrus (not kidding) suddenly falls out of a tree at the exact time that a...
a boat takes 3.1 hours to travel 15 km down a river, then takes 5.1 hours to travel the same distance upstream. how fast is the river traveling.
I found the boat is traveling at 4.84km/hr down the stream and 2.94 km/hr up it. not sure where to go next.
Any help would be appreciated.
Homework Statement
Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 6.00m. The stones are thrown with the same speed of 9.0m/s. Find the location (above the base of the cliff)...
Homework Statement
Car A is located 43km away, 17 degrees north of west. Car B is 34km away, 38 degrees east of north. The person in car A checks the position of car B by using a GPS. What does it give for car B's
a) distance from car 1
b) direction, measured due east?
Homework Equations...
Homework Statement
a baseball player hits a home run that just clears a fence that is 19.0 meters high.The fence is located 128 meters from the home player(where the ball is hit). The ball was hit at an angle of 37.0 degrees above the horizontal from a height of 0.900 meters above the ground...
Homework Statement
A rifle is aimed horizontally at a target 50m away. The bullet hits the target 2.5cm below the aim point.
A) Find the bullets flight time.
B)Find the bullets initial velocity upon leaving the barrel.
Homework Equations
Projectile kinematic equations/
The Attempt at a...
Homework Statement
Sam is running at 3.8 m/s and is 75m behind John who is running at a constant velocity of 4.2m/s. If Sam accelerates at 0.15m/s^2, how long will it take him to catch John?
Homework Equations
d = (vf+vi/2)t
vf = vi + at
d = vit + 1/2at^2
vf^2 = vi^2 + 2ad
d = vft -...
Homework Statement
A student riding a bicycle begins to go downhill and accelerates at a rate of 1.8m/s2. If the acceleration lasts for 2.4s, and the final speed of the bicycle is 10.2m/s, at what speed was he initially travelling?
a = 1.8
t = 2.4
vf = 10.2
vi = ?
Homework Equations...
I don't know what to do for these three questions and they're due on Wednesday
Homework Statement
a. A sprinter can accelerate with constant acceleration for 2.28s before reaching top speed.
He can run 148.0m in 16.6s. What is his speed as he crosses the finish line?
b. A car...
I'm using a Quantum Physics student textbook for physics at school. My class started with Kinematics and I want to know what pages I should read to better understand the topic.
Homework Statement
A man decided to run a marathon.
(a) What was his average speed, in m/s, for the first 5K?
(b) At 5K, was he speeding up or slowing down? Explain. Homework Equations
a) change in distance/time
b) acceleration = change in velocity/ change in timeThe Attempt at a Solution...
Homework Statement
A pole-vaulter leaves the ground with an upward speed of 9.5 m/s.
(a) How fast is she going when she is 2.0 m above the launch point?
(b) How long is required to reach this height?
(c) Why are there two answers to (b)?
The Attempt at a Solution
Question A and...
Homework Statement
You throw a snowball with an initial speed of 15.0 m/s. Your enemy's head is located 20m away, approximately horizontally. At what angle should you throw the snowball (ignore air resistance)?
Homework Equations
vf=vi+at
d=vit+(1/2)at^2
The Attempt at a Solution
Im sorry I just realized this is in the wrong subforum...
Homework Statement
Hello Everyone! I am new here and am having trouble with this webassign question. I was able to work out the answer to the first two but the last two are giving me trouble. I am not sure if this is right subforum to...
Hello everyone,
I've run across an interesting Newtonian physics problem that I'd like some input on. The problem begins with a rotating object. Let's assume it is a slender rod rotating about one end with a given mass (m), length (L) and rotational speed (ω). This results in the rod having...
Homework Statement
A cross country team race is about to begin and team Beta decides to use their one-dimensional kinematics knowledge that they learned from their first year physics course. Each team consists of two people and one horse. The clock is started when the team crosses the...
Homework Statement
I know pictures aren't the best, but here it is.
Homework Equations
The Attempt at a Solution
This is my work for this problem. Disregard the drawing as it isn't right.
I'm not sure if I'm misinterpreting the horizontal range part or what. I feel pretty...
Kinematics question -- Rocket launch
Homework Statement
A rocket starts from rest and moves upward from the surface of the earth. For the first 10s of its motion, the vertical acceleration of the rocket is given by ay=(2.70m/s3)t, where the +y-direction is upward.
A.What is the height of the...
kinematics question -- An automobile accelerating and braking
Homework Statement
According to recent test data, an automobile travels 0.250 mi in 19.9 s, starting from rest. The same car, when braking from 60.0 mi/h on dry pavement, stops in 146 ft. Assume constant acceleration in each part...
Please help. I think I may be over thinking this problem because it looks very simple.
Homework Statement
Determine the minimum initial velocity, v0, and corresponding angle, θ0 needed to kick the ball just over the 3m high fence.
x = 6m
y = 3m
Homework Equations
X:
vx=v0x
x = x0+v0xt
v0x...
Hey guys so I have a quick question about the algebra for a question like this.
I personally like to do the algebra first before I plug in the numbers so I have question for this one where it seems would be safer to plug in the numbers first?
So won't be to tough,
A book falls from a...
Can anyone define the distinction between the laws of nature and the kinematics of nature? I am thinking that laws have more to do with forces and potentials and kinematics have more to do with velocities and reference frames but I cannot formulate a clear definition of one that does not overlap...
Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :)
Part B
1) A golfer hits a nice iron shot and the ball's height above the ground is given by h(t) = -16t^2 + 80t, where t is the time in seconds since the ball was...
a man moves in an open field such that after moving 10 m on a straight line he makes a sharp turn of 60 degree to his left .the total displacement after 8 such turns is equal to
given below is a more than one choice type MCQ,
A ball is bouncing elastically with a speed 1 m/s between walls of
a railway compartment of size 10 m in a direction perpendicular
to walls. The train is moving at a constant velocity of 10 m/s parallel
to the direction of motion of the ball...
1. Homework Statement
the question is:
A 62 kg person in an elevator is moving up at a constant
speed of 4.0 m/s for 5.0 s. T / I C
(b) Calculate the work done by the normal force on the person.
(c) Calculate the work done by the force of gravity on the
person.
(d) How would your...
Homework Statement
W(oa) = -5k
α(oa) = 3k
B = 30 deg
B(dot) = -2cos 30i + 2sin30j = Vrel
b(double dot) = 4cos30i - 4sin30j)
Homework Equations
Va = Woa x Rao + Vrel
The Attempt at a Solution
This is such a simple problem and I don't know why I am messing it up. I am just...
Homework Statement
Two cyclists are in a race. One cyclist knows that he is slower, so he cheats: he removes the faster cyclist’s bike chain. The cheater starts from rest immediately with acceleration 2.5 m/s2. The faster cyclist has to take 3 seconds to replace her bike chain. She then...
Homework Statement
You must determine the acceleration of a rocket so that its equipment can be designed to survive. The rocket will have a burn time of t = 30 seconds, during which time it flies has a constant acceleration a. Call this Phase 1. After the fuel is exhausted the rocket enters...
Hi PF, I'm reviewing my notes from class, starting from the very beginning. I'm working on some problems using kinematic equations. Here's one example: a ball falls from 30m (using down as the positive direction) at a velocity of 8 m/s. how long does it take the ball to hit the ground?
Why do I...
A firecracker with mass 100g is propelled vertically with a launch force of 1.2N applied over 5s, after which it explodes into two 50g fragments. One fragment goes horizontally at 15m/s and the other goes to the right at angle 53 degrees with the horizontal at speed 25 m/s. find the distance...
Homework Statement
A football player attempts a 30m field goal. If he is able to impart a velocity u of 30 m/s to the ball,compute the minimum angle θ for which the ball will clear the crossbar of the goal. (Hint: Let m = tanθ .)
Homework Equations
V0x = V cosθ
V0y = V sinθ
We get t...
Homework Statement
There are two rods with one having ring "P" and the other having ring "Q". The rings are connected by a massless and inextensible string which is then connected from "Q" to ceiling. If ring "Q" moves down with velocity "v", what is the velocity of ring "P" ? The string...
Homework Statement
A skidding car starts moving with a velocity of 6.75m/s at an angle of 58.82657 degrees north of east. Its velocity just before it comes out of its skid 4 seconds later is 3.25 m/s at an angle of 49.6091 degrees south of east. It travels with a constant acceleration while it...