US STOCKS-Economic worry drags market, GM tumbles

* Optimism over China stimulus plan fades

* Worries about GM's future hurts sentiment, stock plunges

* McDonald's jumps after sales top expectations

* Dow off 0.5 pct, S&P 500 off 0.9 pct, Nasdaq off 1.2 pct (Updates to midday)

By Ellis Mnyandu

NEW YORK, Nov 10 (Reuters) - U.S. stocks dipped on Monday as investors expressed doubts about whether China's deep-pocketed stimulus plan would avert a global economic slump and shares of General Motors (GM.N: Quote, Profile, Research) fell to 62-year lows on worries about the carmaker's dwindling cash.

A slide of more than 20 percent in the shares of GM, a Dow component, offset a gain of more than 2 percent in the shares of McDonald's Corp (MCD.N: Quote, Profile, Research) , whose October same-store sales beat estimates.

The slide in GM shares followed Deutsche Bank's "sell" recommendation and negative comments from other brokerages that the auto maker and its rivals are burning through cash fast.

Stocks worldwide initially rose on news that China had approved a $586 billion stimulus plan that could mean stronger demand for world markets.