Posted by lola on Saturday, December 18, 2010 at 4:06pm.
A ball is placed at the top of a hill of incline 60.0 degrees. The ball is
allowed to roll for 12.0 seconds. How far will the ball roll during this
period? Neglect friction.

phyics  bobpursley, Saturday, December 18, 2010 at 4:23pm
Neglect friction, but the ball is rolling? What makes is roll? Remember, you said neglect friction.
Assuming there is friction, at least enough to rotate the ball, then the ball falls some vertical distance h.
This corresponds with incline distance L=h/sin60
1/2 m v^2+1/2 I w^2=mgh
but w=v/r, and I for a solid ball is 2/5 m r^2
1/2 m v^2+1/2 2/5 mv^2=mgh
v^2(1/2 +1/5)=gh
v= sqrt (gh/(3.5/5))
this is final velocity,so average velocity is 1/2 v or 1/2 sqrt (5gh/3.5)
how far did it go? in 12 seconds?
distance down the hill= v*t=6sqrt(5gh/3.5)
check my thinking.

physics  drwls, Saturday, December 18, 2010 at 5:16pm
If there is friction, and the ball rolls, the rate of acceleration depends upon the moment of inertia of the ball. Is it hollow or solid? These things male a difference.
It is quite unlikely that a ball will slip and fail to roll, but that seems to be what they want you to assume.
Answer This Question
Related Questions
 physics  A 5.0 ball is initially sitting at rest on top of a 41 m high hill. ...
 Physics  A ball rolls down an incline at a constant acceleration of 2 m/s^2. ...
 physics  starting from rest, a ball rolss, down an incline ata constant ...
 science  In the diagram above, the arrows represent momentum. A larger arrow ...
 physics rewrite  starting from rest, a ball rolls, down an incline at a ...
 Physics  Circular motion  A marble of mass m is placed on top of a bowling ...
 physics  A spherical bowling ball with mass m = 4.1 kg and radius R = 0.116 m ...
 Physics  A solid and a hollow ball, each with a mass of 1 kg and radius of 0.1 ...
 science  1.a ball with a mass 2kg rests on an incline with an angle of 10 ...
 science please help  1.a ball with a mass 2kg rests on an incline with an angle...
More Related Questions