A uniform 1-kg disk with a radius of 25 cm rolls 2 m down an incline plane angled at 25 $\circ$ .What is the speed of the disk at the bottom of the plane?
A)4.07 m/s
B)3.32 m/s
C)5.43 m/s
D)6.26 m/s
E)1.24 m/s

Question

Quizplus · Accepted Answer

We can find the gravitational potential energy (GPE) of the disk at the top of the inclined plane:
GPE = mgh = (1 kg)(9.81 m/s^2)(2 m) = 19.62 J
At the bottom of the plane, all of the GPE is converted to kinetic energy (KE) of the disk:
KE = 1/2mv^2
19.62 J = 1/2 (1 kg) v^2
v = √(39.24/1) = 6.26 m/s
Therefore, the speed of the disk at the bottom of the plane is 6.26 m/s, which corresponds to choice (B).

A Uniform 1-Kg Disk with a Radius of 25 Cm ∘\circ∘

A Uniform 1-Kg Disk with a Radius of 25 Cm $\circ$