Help Laws of Motion and question help

In summary, the train initially accelerates uniformly for 30.0 seconds over a distance of 225 m and then continues at the same speed for another 135 seconds. The driver then applies the brakes and the train comes to rest with uniform retardation in 10.0 seconds. Using the equation s= ut + 1/2at^2, the acceleration can be calculated and found to be 0.5 m/s^2. With this information, the distance between the two stations can be calculated by finding the change in distance over the 135 seconds at this acceleration.
  • #1
physicsguru97
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Homework Statement


A train moves off from a station and accelerates uniformly for 30.0 s over a distance of 225 m. It continues with the speed acquired for another 135 s, then the driver applies the brakes and the train comes to rest with uniform retardation at the next station in a further 10.0 s. Calculate the distance between the two stations


Homework Equations



s= ut + 1/2at^2


The Attempt at a Solution


i am still stuck please someone help me go through the steps
 
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  • #2
Can you find the acceleration over the 225m distance given you have time?
 
Last edited:
  • #3
No I don't understand which time to use
 
  • #4
well the question states that the train travels 225m in 30s - try using these.
 
  • #5
So I divide those 2 then times it by 135 to get the acceleration?
 
  • #6
use the equation you stated, s= ut + 1/2at^2
 
  • #7
But I don't know how to get acceleration would u be 0 because it started from rest and is the time 30 if I put in equation?
 
  • #8
that is correct.
 
  • #9
Yes but how do you get acceleration?
 
  • #10
as i said before use this equation... s= ut + 1/2at^2
you know what s, u, and t are can you not solve the equation for a?
 
  • #11
a = 2(s - ut)/t^2 would I rearrange to this??
 
  • #12
Yes that is correct however you know that u=0 right? because as you said earlier the train starts from rest, and u represents the initial velocity of the train.
 
  • #13
Yes I know that so after I've calculated the acceleration what do I do next?
 
  • #14
Well what you're trying to do is find the total distance to the second train station... so you're told the train travels at this acceleration you've found for another 135s, you need to find the change in distance with this acceleration.
 

What are the three laws of motion?

The three laws of motion are:
1. Newton's First Law - also known as the Law of Inertia, states that an object will remain at rest or in constant motion unless acted upon by an external force.
2. Newton's Second Law - also known as the Law of Acceleration, states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass.
3. Newton's Third Law - also known as the Law of Action and Reaction, states that for every action, there is an equal and opposite reaction.

How do the laws of motion apply to everyday life?

The laws of motion apply to everyday life in many ways. For example:
1. Newton's First Law can be seen when you are in a moving vehicle and suddenly come to a stop. You continue to move forward because of inertia until an external force (like a seatbelt) stops your motion.
2. Newton's Second Law can be seen when you push a shopping cart with a heavier load and it requires more force to accelerate it.
3. Newton's Third Law can be seen when you jump off a diving board and your feet push down on the board, causing the board to push back up with an equal force.

What is the relationship between force, mass, and acceleration?

According to Newton's Second Law, force, mass, and acceleration are all related. The greater the force applied to an object, the greater its acceleration will be. However, the mass of the object also plays a role. The more massive an object is, the more force is needed to accelerate it at the same rate. This can be seen in the formula F=ma (force = mass x acceleration).

How does understanding the laws of motion benefit us?

Understanding the laws of motion allows us to explain and predict the motion of objects in our everyday lives. This knowledge is essential in fields such as engineering, transportation, and sports. It also helps us understand the behavior of objects in space and has allowed us to develop technologies such as rockets and satellites.

What is the difference between speed and velocity?

Speed and velocity are often used interchangeably, but they are actually different concepts. Speed is a measure of how fast an object is moving, while velocity is a measure of how fast an object is moving in a specific direction. In other words, velocity takes into account both speed and direction, while speed only considers the magnitude of the object's motion.

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