Solve Kinematics Problems Before Wednesday

  • Thread starter Thread starter PandaBunny
  • Start date Start date
  • Tags Tags
    Kinematics
AI Thread Summary
The discussion revolves around three kinematics problems due on Wednesday, focusing on a sprinter's speed, a car's initial velocity, and the speed of a car with a rocket and parachute. Participants emphasize the importance of understanding the equations governing accelerated motion and suggest using a structured problem-solving approach known as GRASP. The advice includes breaking down each problem into given quantities, required outcomes, relevant equations, and then solving them step-by-step. There is a sense of urgency as the deadline approaches, and contributors encourage sharing attempts for collaborative help. The overall tone is supportive, urging the original poster to remain calm and methodical in tackling the problems.
PandaBunny
Messages
2
Reaction score
0
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 accelerates at 2.15m/s2 along a straight road.
It passes two marks that are 29.5m apart at times t=3.95s and t=4.85s.
What was the car's velocity at t=0?

c. You've attached a rocket to the rear of a small car
The rocket provides a constant acceleration for 4.68s.
As the rocket shuts off, a parachute opens and slows the car at a rate of 3.43m/s2.
The car passes the judges' box, 878.0m from the starting line, exactly 14.0s after you fire the What is the car's speed as it passes the judges?

Homework Equations





The Attempt at a Solution



I don't even know where to start I'm just too stressed
 
Physics news on Phys.org
Chill and start by recalling what equations govern accelerated motion.

It is also suggested that you post one problem at a time.
 
First, Don't panic! Second, somebody on here quoted a problem-solving methodology I didn't know - GRASP. It stands for

Given - list the quantities that are in the question.
Required - list the quantities that you are supposed to find.
Asess - what equations do you know that link the things that you listed? Your textbook's index is helpful if nothing springs to mind.
Solve - do the maths.
Paraphrase - write out the answer.

See if you can do the first three at least.
 
I've tried to solve it already but I'm just not getting the right answers, I just need to see how someone else goes about solving it before I try it again
 
If you want help, post your work so far. We won't do your HW for you. You don't have much time left.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top