Motion with Constant Acceleration

Thread starter JustGracie
Start date Oct 30, 2009
Tags

Acceleration Constant Constant acceleration Motion

AI Thread Summary

The discussion centers on a problem involving a motorcyclist who decelerates uniformly over 3.2 seconds, covering a distance of 40 meters before stopping. Participants suggest using the kinematic equation s = (u + v)/2 * t to solve for the initial velocity. It is noted that finding the acceleration first could simplify the calculation of the initial speed. The conversation emphasizes the importance of understanding kinematic equations in solving motion problems. Ultimately, the goal is to determine the motorcyclist's initial speed before he began to slow down.

Oct 30, 2009

JustGracie

1. The problem
A motorcyclist slows down uniformly as he approaches a red light. He takes 3.2 seconds to come to a halt and travels 40m in this time.
How fast was he traveling initially?

Homework Equations

s=(u+v)/2*t

Physics news on Phys.org

Oct 30, 2009

XanziBar

Any other kinematic equations? If you can find his acceleration, I bet you could find his initial velocity.

Thread 'Errors and significant figures'

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...

View full post »

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...

View full post »

Thread 'Explain this asphalt sheen'

This problem is two parts. The first is to determine what effects are being provided by each of the elements - 1) the window panes; 2) the asphalt surface. My answer to that is The second part of the problem is exactly why you get this affect. And one more spoiler:

View full post »