40 I believe because the space of the auto mobile catching up to the train is 4 hours. 4 times 30 is 120 miles so u need to figure out a number that can reach 120 in three hours. 3 times 40 is 120
6 / (2/5) = 15
It should take the nail 15 minutes to crawl 6 meters.
Answer:
Answer:
safe speed for the larger radius track u= √2 v
Explanation:
The sum of the forces on either side is the same, the only difference is the radius of curvature and speed.
Also given that r_1= smaller radius
r_2= larger radius curve
r_2= 2r_1..............i
let u be the speed of larger radius curve
now, \sum F = \frac{mv^2}{r_1} =\frac{mu^2}{r_2}∑F=
r
1
mv
2
=
r
2
mu
2
................ii
form i and ii we can write
v^2= \frac{1}{2} u^2v
2
=
2
1
u
2
⇒u= √2 v
therefore, safe speed for the larger radius track u= √2 v
So we need have to understand that if we were to solve this, our answer would be 7 less than 'p' with that information we get p-7.
