How far did the ball roll during the first 5 seconds of its motion?

[mayeh]

pls. help --> acceleration

Homework Statement

a ball starts from rest and rolls down a hill with a uniform acceleration traveling 150m during the second 5.0s of its motion. How far did it roll during the first 5.0s of its motion

pls. help

Homework Equations

The Attempt at a Solution

 

[ron_jay]

what have u tried so far so that we can help u?

 

[mayeh]

i tried to get its acceleration and i got a 3m/s^2, but after that i don't know what to do, I'm not even sure if i got it right.

 

[ron_jay]

What you have to see first is that the distance traveled by the rolling ball in the next 5 seconds is nothing but the difference between the distance traveled by the ball in 10 seconds and the distance traveled in 5 seconds.

By the simple kinematic equation, we know that:

S=ut+(1/2)at^2

Since the initial velocity u is 0, the ut component of the equation goes and only (1/2)at^2 is left.So the distance traveled in the next 5 seconds is nothing but:

(1/2)a{(10^2)-(5^2)}=150

Solve for 'a'.(It wouldn't work out to 3m/s^2.)
Now, u know 'a' so substitute it in the equation (1/2)a.5^2 to get the answer!