Problem 1

A small block of mass

m

is released from rest at the top of a fixed, smooth spherical dome of radius

R

and slides down its outside; take gravitational acceleration

g

as constant. The angle

\theta

is measured from the vertical through the top to the radius through the block, with

0\le\theta<\pi/2

. Neglect the block's size and drag. (a) Use energy conservation to find its speed as a function of

\theta

. (b) Write Newton's second law radially and state the loss-of-contact condition. (c) Find the departure angle and explain why it is independent of

m,R,g

problems.proof.stepOf

problems.proof.prevStep problems.proof.nextStep

v^2=2gR(1-\cos\theta)

problems.proof.analysis

Cancel the positive mass in the energy equation. This squared speed can be substituted into the force equation; at the top, $\theta=0$ gives $v=0$ as required.