Find how long a marble rolls down a ramp, given distance and angle

AI Thread Summary
To determine how long a marble takes to roll down a 5.0 m ramp at an angle of 6.9°, the correct answer is 2.9 seconds. The relevant equations include v = at and d = 1/2at², but the angle's effect on acceleration must be considered. The angle influences the time it takes for the marble to reach the bottom, as a steeper angle results in a shorter time. Participants in the discussion emphasize the importance of calculating the acceleration component down the ramp. Understanding the relationship between the ramp's angle and the marble's acceleration is crucial for solving the problem accurately.
camelCaseD
Messages
5
Reaction score
0

Homework Statement


How many seconds does it take a marble to run down a ramp with a length of 5.0 m and an angle of 6.9°?
Correct answer = 2.9 s.

Homework Equations


v = at
d = 1/2at2

The Attempt at a Solution


√2(5)/9.8≠2.9 s
 
Physics news on Phys.org
hi camelCaseD! welcome to pf! :smile:

where did you use the 6.9° ? :confused:

(or the fact that it rolls)
 
I'm not sure if the angle is relevant information for solving the problem or not. But the length of the ramp and the angle its at are the only given data I have. The marble does roll down the ramp.
 
camelCaseD said:
I'm not sure if the angle is relevant information for solving the problem or not.

?? :confused: but if this 5m ramp was at 0.01°, wouldn't it take a lot longer than if it was at 90° ?
 
tiny-tim said:
?? :confused: but if this 5m ramp was at 0.01°, wouldn't it take a lot longer than if it was at 90° ?
Yes it would be slower if the angle were 0.01° than 90°.
 
yes! :smile:

sooo … ? :wink:
 
So then since the angle of the ramp is at 6.9° the time it would take the marble to roll down the ramp would take longer than if it were straight up and down.
 
yes, but what equation are you going to use?

(and now I'm off to bed :zzz:)
 
  • Like
Likes 1 person
I'm going to use the equation d=1/2at2
 
  • #10
(just got up :zzz:)
camelCaseD said:
I'm going to use the equation d=1/2at2

yeeees …

but first you need to find a (the component of acceleration down the ramp)!​

what equation will you use for that? :smile:
 
Back
Top