0
Newtons Laws of Motion
The three laws proposed by Sir Isaac Newton to define the concept of a force and describe motion, used as the basis of classical mechanics.
1,508 Questions
Are reaction forces always created after the action force?
I suppose this in a way depends on perspective at hand.
A reaction force is directly opposite of action force.
If a ball hit another ball, they actually hit each other at the same time with the same force if they are of the same size and mass.
If a ball hit a football player, then the football player equally hit the ball but in proportion to mass. This happen at the same time.
Now for the tricky part.
The action force could be considered to trigger a reaction force different to what it would normally be because it is observed. Would this not make reaction force before action force?
Still probably not valid.
As a reaction force is directly opposite of action force, it would not matter if the football player hits the ball hard or not so hard as a result of what he sees. Energy exchanged will be different, but always in proportion to mass.
The football player would only be exchanging action and reaction force with other objects/players before hitting the football, making another exchange of energy.
Claim:
All exchange of energy happens at the same time for both objects in proportion to their mass no matter the circumstances.
Newtons third law.
What law of of newtons law deal with objects in motion?
The following Newton's law deal with motion.
1. Every body continues in its state of rest or of uniform motion in a straight line path until and unless and external force is applied.It is also called as law of inertia.
2. The rate of change of momentum is directly proportional to the force applied and the change takes place in the direction of applied force.
3. For every action there is an equal and opposite reaction. Forces exist in pairs.
Does the moments of Inertia change if center of mass change?
No, the moment of inertia of an object does not change with a change in its center of mass. The moment of inertia depends on the mass distribution and shape of an object, not its center of mass.
An object is in motion only if its distance from a reference point is?
An object is in motion only if its distance from a reference point is changing. The average speed of the object is given by the object's rate of change of displacement from the reference point over time.
How can nawtons first law be derived from newtons second law?
The Second Law is Force = Mass times Acceleration. The First Law can be derived from the Second Law by setting the Focre to zero or the Acceleration to zero;. No force = no acceleration; or No acceleration = no force.
How is intera involved in newton's first law of motion?
An object's inertia is the object's resistance to change in motion.
Newton stated this principle as his first law of motion:
"Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed."
Restated:
"An object that is at rest will stay at rest until an unbalanced force acts upon it. An object that is in motion will not change its velocity until an unbalanced force acts upon it."
What are similarities between balanced forces and action reaction forces?
There is no such thing as a balanced force or an unbalanced force. A group
of two or more forces may be balanced or unbalanced. The group of forces is
balanced if the vector sum of all the forces in the group is zero.
Describe situation where newton's 3rd law is operating?
The most common example is that you throw a ball at the wall, it comes back to you.
You do the action and then wall does the reaction by returning the ball with equal magnitude but in a direction opposite to your action.
Using the equation for acceleration a = F/m, where F is the net force and m is the mass, we can find that the acceleration of the box is 2 m/s^2. Using the equation v = at, where v is the final velocity, a is acceleration, and t is time, the speed of the box at the end of the 5 second interval is 10 m/s.
Use the formula v2=u2+2*a*s
v=final velocity
u=intital velocity
a=acceleration due to gravity
s=displacement
This then gives:
2*9.8*5
=98
square root of 98
9.89ms-1
Velocity change can result in changes in an object's speed and/or direction of motion. This change in velocity can be caused by forces such as acceleration, deceleration, or changes in direction, which can affect the object's kinetic energy and momentum.
Friction is a force that opposes the motion of an object. The net force on an object is the sum of all the forces acting on it, including friction. If the net force is greater than friction, the object will accelerate. If friction is greater than the net force, the object will not accelerate and may start sliding on the surface due to the imbalance of forces.
What is a scalar which is both positive and negative?
Scalar is a type of quantity which contains magnitude only and has no direction.
For example: distance and speed
Balanced forces do not cause what?
Balanced forces do not cause changes in an object's motion or acceleration. When two forces are balanced, their magnitudes and directions cancel each other out, resulting in no net force acting on the object.
How much force is needed to bring a 3200 lb car from rest to a velocity of 44ftsec in 8 sec?
How much force is needed to bring a 3200 lb car from rest to a velocity of 44ftsec in 8 sec?
a = (vf - Vi)/time
a = (0 - 44)/ 8
a = -5.5 m/s^2
F = m * a
Since the weight is given in pounds, gravity = 32.2 m/s^2
W = m*g
3200 = m * 32.2
m = 99.4 Slugs
At least that is what we used to call mass in the English system
F =99.4 * -5.5
F = -546.7 lbs.
As strange as it may seem at first, the ball is actually moving towards the center, its just that when the centripetal force pulls the ball towards the center, the objects preexisting speed moves it to another spot on the circle, stopping it from actually spiraling inwards.
One way to visualize this is to imagine that you throw a ball. Under normal circustance, when you throw the ball, it will go forward for a little bit but it will eventually be pulled down by gravity and hit the ground. Now, imagine that you could throw the ball so fast that by the time it falls 10 feet, it has gone far enough out form the Earth that there is another 10 feet to go before it reaches the ground. Thus, even though the ball is getting pulled towards the Earth, its falling as fast as its moving.
Its this combination of falling and moving that actually creates the circular motion. If the falling is faster than the moving, the object will just eventually spiral into whatever is pulling on it. Alternatively, if the moving is faster than the pulling, there will be an overall hyperbolic path, as the object gets close to the source of the pul but then shoots away.
What is the difference between Newton's first law of motion and Newton's third law of motion?
The 1st law says that changes in motion are caused by forces.
The 2nd law says that the force applied to an object causes acceleration.
The 3rd law says that when a force is applied it causes equal and opposite changes in momentum so that the vector sum of momentum is zero.
If an object is moving at unifrom acceleration what is its velocity?
A body moving at a uniform speed may have a uniform velocity, or its velocity could be changing. How could that be? Let's look. The difference between speed and velocity is that velocity is speed with a direction vector associated with it. If a car is going from, say, Cheyenne, Wyoming to the Nebraska state line at a steady speed of 70 miles per hour, its velocity is 70 miles per hour east. Simple and easy. Uniform speed equals uniform velocity. (Yes, I-80 isn't perfectly straight there. Let's not split hairs.) But a car moving around a circular track at a uniform speed is constantly changing direction. Its speed is constant, but its velocity is changing every moment because the directionit is going is changing. Speed is uniform, but velocity isn't. As asked, uniform speed is a uniform distance per unit of time. And this will yield a uniform distance per unit of time in its velocity, but the direction vector may be uniform or it may be changing each moment, as illustrated.
Action reaction force pairs act on what?
All Forces! For every action there is an equal and opposite reaction.
"The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs"
The force of friction is equal and opposite to the applied force in this scenario, so the force of friction on the object would also be 20N. This allows the object to remain in a state of equilibrium and not accelerate.
Examples of newtons first law?
- A ball rolling on a flat surface will continue rolling at a constant velocity unless acted upon by an external force.
- A stationary object will remain at rest, and an object in motion will continue moving in a straight line at a constant speed unless acted upon by an external force.
- If a car suddenly stops, passengers inside the car will continue moving forward due to inertia until a seatbelt or airbag provides the necessary force to stop them.
the buoyant force will remain the same because the rock will displace the same amount of water volume at any depth.
Theoretically, it will gain buoyancy as it sinks, because when an objects density matches the density of the water around it, and water becomes denser as it falls deeper, it will be neutrally buoyant or floating. But since a rock is always going to be more dense than water it would still sink.
An object with mass 'm' moving with velocity 'V' has kinetic energy of [ 1/2 m V2 ] .
In order to bring it to rest, its velocity has to be reduced to zero, and in order to
accomplish that, the kinetic energy has to be drained off and sent somewhere else.
An external force has to absorb energy from the object, i.e. do negative work on it,
equal to its kinetic energy, or
- 1/2 m V2
If a net force of 120N gives an object an acceleration of 1.5 m s s what is the mass of the object?
The mass of the object can be calculated using the formula F = ma, where F is the net force, m is the mass, and a is the acceleration. Rearranging the formula to solve for mass, we get m = F / a. Plugging in the values given, mass = 120N / 1.5 m/s^2 = 80 kg. So, the mass of the object is 80 kg.
At what angle is the resultant force acting?
The angle of the resultant force can be calculated using trigonometry principles such as the Pythagorean theorem and inverse trigonometric functions. Given the magnitudes of the two component forces, you can determine the angle using the formula: angle = arctan(opposite/adjacent). This will help you find the direction in which the resultant force is acting.
