First year kinematics- Please help

In summary, the conversation includes three questions related to physics. The first question involves a scenario where a space tug pulls an asteroid using its ship's engine. The second question asks for the initial acceleration of a released sphere in an equilateral triangle with two known masses. The third question is about finding the acceleration of a block in a pulley system, with one scenario involving a 908 N block and the other involving a 908 N hand pulling. The conversation also includes some discussions about the scenarios and clarifications of terms.
  • #1
Ztalin
8
0
Physics assignment due tomorrow morning... a few questions.

1. At a time when mining asteroids has become feasible, astronauts have connected a line between their 3500kg space tug and a 6200kg asteroid. Using their ship's engine, they pull on the asteroid with a force of 490N. Initially the tug and the asteroid are at rest, 450 m apart. How much time does it take for the ship and the asteroid to meet?

This one I'm just having trouble picturing it. I don't even know what a space tug is. Are the "ship" and "space tug" synonymous? Hmmm...

2. Three uniform spheres are located at the corners of an equilateral triangle. Each side of the triangle has a length of 1.2m. Two of the spheres have a mass of 2.8kg each. The third sphere (mass unknown) is released from rest. Considering only the gravitational forces that the spheres exert on each other, what is the magnitude of the initial acceleration of the third sphere?

For this one... I don't see how you can get the acceleration of the 3rd sphere without its mass.

3. There is a pulley apparatus with a 412 N block on one end, and a 908 N block on one end. It asks for the accleration and I find it. For part (b), there isn't a 908 N block, but instead, there is a hand pulling with a force of 908 N. It says "Find the accleration of the remaining block. Explain why the answers in part a and b are different. Don't know why they'd be different if both forces are 908 N...

Any help is greatly appreciated. Thanks in advance.
 
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  • #2
Re 1, yes, a tug is a ship in this case. It comes from tug boat that pulls other boats on a line. Tug means pull.
 
  • #3
So if it's pulling it, wouldn't it be moving at the same speed as the asteroid? If so, how would the asteroid then ever catch up to it?

I'm assuming that it's pulling it with a string since it said line... but it's probably with some other mechanism. I'm probably making it harder than it is, and the tug probably doesn't move at all.

Still completely stuck with the other 2 though. And thank you.
 
  • #4
Ok you guys:

I think for the tug that it's like a fishing reel. But if that's the case, wouldn't both masses undergo a force of 490 N? Then Newton's 3rd law would come into play, and they would both move at the same time. So I can probably get this one.

I know how to do the second one now... I forgot to split up the force equation so that it's independent of the second mass.

As for the pulley question, I still don't know why they'd be different either.

So is anyone can tell me why it would be different for pulling it with a hand (why is pulling at 908 N different than having a weight of 908 N doing it due to gravity?)
 

1. What is kinematics?

Kinematics is the branch of physics that studies the motion of objects without considering the causes of that motion. It focuses on describing the position, velocity, and acceleration of an object as it moves.

2. What is the first year kinematics course about?

The first year kinematics course typically covers the basic principles of kinematics, such as displacement, velocity, acceleration, and motion in one and two dimensions. It also introduces students to equations and graphs used to analyze and describe motion.

3. What are some real-life applications of kinematics?

Kinematics has many real-life applications, such as predicting the trajectory of a projectile, understanding the motion of planets and satellites, and analyzing the movements of athletes in sports. It is also used in fields such as robotics, animation, and video game development.

4. How can I improve my understanding of first year kinematics?

To improve your understanding of first year kinematics, it is important to practice solving problems and working with equations and graphs. You can also try visualizing different scenarios and applying kinematics principles to them. Seeking help from a tutor or joining a study group can also be beneficial.

5. What are some common challenges students face in first year kinematics?

Some common challenges students may face in first year kinematics include understanding the concepts and equations, applying them to different scenarios, and visualizing motion in multiple dimensions. Time management and problem-solving skills can also be important factors in succeeding in the course.

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