Angular motion problem involving a car coming to a stop

AI Thread Summary
The problem involves a car decelerating from 12.0 m/s at a constant rate of 1.90 m/s², leading to a stopping distance of 37.89 meters. The calculation for the angle in radians is based on the distance traveled divided by the tire radius of 0.40 m, resulting in 94.725 radians. The conversion to revolutions yields approximately 15.075 revolutions, which was initially miscalculated as 115.076. Participants suggest checking the math and ensuring the correct use of significant figures in the final answer. The discussion highlights the importance of accuracy in calculations and proper unit conversions.
xregina12
Messages
26
Reaction score
0
The driver of a car traveling at 12.0 m/s applies the brakes and undergoes a constnant decelertion of 1.90m/s^2.
How many revolutions does each tire make before the car comes to a stop assuming that the car does not skid and that the tires of radii of 0.40 m? answer in units of rev.

I used the equation Vf^2=Vi^2+2ad
0=144+2(-1.90)(d)
d=37.89meters
d=r(θ)
θ=37.89/0.40=94.725 radians
revolutions=94.725/(2pi)=115.076 revolutions.
However, I did not get a correct answer. Can anyone help?
 
Physics news on Phys.org
revolutions=94.725/(2pi)=115.076 revolutions.

Is this a typo? Check your math here.
 
I meant to write 15.075 and it's still not right though.
 
I don't see what's wrong with that answer. Are you using correct sig figs when you enter your answer?
 

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'

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 »

Similar threads

Angular motion problem (wheels on a car coming to a stop)
Replies
1
Views
3K
How to calculate angular speed?
Replies
7
Views
2K
Calculate velocity of stopping car
Replies
7
Views
2K
Circular Motion With Constant Angular Acceleration
Replies
3
Views
2K
Angular Velocity and Acceleration
Replies
10
Views
2K
Car Crash Analysis: Analyzing Friction & Speed
Replies
9
Views
4K
Calculating Revolutions for a Spinning Wheel | Circular Motion Problem
Replies
18
Views
2K
Rotation w/constant angular acceleration
Replies
2
Views
3K
Calculating Acceleration for a Car Stopping on a Dime: Kinematics Question Help
Replies
7
Views
2K
Calculating Tire Revolutions and Angular Speed in a Braking Car
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top