A small rock with a mass of 0.300 kg is released from rest at point A, which is at the top edge of a large, hemispherical bowl with a radius R = 0.560 m View Figure . Assume that the size of the rock is small compared to the radius of the bowl, so that the rock can be treated as a particle, and assume that the rock slides rather than rolling. The work done by friction on the rock when it moves from point A to point B at the bottom of the bowl is - 0.290 J.
What is the speed of the rock when it reaches point B? g = 9.81 m/s^2 for the acceleration due to gravity.
2006-06-28 19:45:21 · 6 answers · asked by Ronaldinho G 1 in Science & Mathematics ➔ Physics
Starting from the Principle of Conservation of Energy, initial Potential energy at the top is equal to the energy lost and the final kinetic energy of the rock.
The Potential energy the rock has= Mass x Accn due to free fall x height
= 0.300 Kg x 9.80 ms^-2 x 0.560 m
=1.6464 J
Therefore, the kinetic energy the rock has is = 1.6464 J - 0.290 J
=1.3564 J
Kinetic energy = (1/2) x m x v^2
so the velocity is = square root of ( 2 x 1.3564 J) / 0.300 Kg
=3.007... ms^-1
=3.01 ms^-1 <3SF>
2006-07-02 08:30:11 · answer #1 · answered by sexy_blue7 2 · 0⤊ 0⤋
For all the trouble, the best answer cannot get more than 10 points at the present rating pattern. So attempting for 30 points is a mission impossible.
2006-06-28 19:51:50 · answer #2 · answered by Spiritualseeker 7 · 0⤊ 0⤋
potential energy of the rock =mgh=0.3*9.81*0.56=1.64808J
less the loss due to friction=0.290J
kinetic energy as the rock reaches the bottom=1.35808J
1/2*0.300*v^2=1.35808
v^2=9.0538667 and so v is approximately 3m/s
2006-06-30 01:22:39 · answer #3 · answered by raj 7 · 0⤊ 0⤋
Initial potential energy=mgh=0.3*9.81*0.56=1.64808 J
Energy lost as friction=0.29 J
Kinetic energy left=1.64808-0.29=1.35808 J
Kinetic energy = 0.5mv^2 = 1.35808 J
Therefore, speed = 3.00896 m/s^2
2006-06-28 19:54:56 · answer #4 · answered by peaceharris 2 · 0⤊ 0⤋
Its not impossible, just use the work-kinetic energy theorem. Or derive this relationship from the conservation of mechanical energy.
But do your own homework.
If you have questions we would be more than happy to answer.
You dont understand mechanics by looking at other peoples solutions you understand it by using reasoning to deduce a method of solution. And practicing this.
2006-06-28 19:50:53 · answer #5 · answered by Richardicus 3 · 1⤊ 0⤋
how do u give 30 points???
2006-06-28 19:48:36 · answer #6 · answered by ayleyha 3 · 0⤊ 0⤋