Amid tumultuous applause, President-elect Ronald Reagan attended three concerts at the Kennedy Center last night near the end of a long second day of pre-inaugural activities that filled the city's streets with glittering, siren-blaring motorcades and massive, frustrating traffic snarls.

Throughout the day the expectation that the hostages in Iran soon would be released appeared to enhance the sense of excitement generated by the anticipation of the swearing in Tuesday of a new president.

Reagan and his wife Nancy went to all three music and dance programs held as part of the Gala Inaugural Concert before returning to their temporary residence at Blair House while revelry and merriment still swirled through the city and searchlight beams from hovering helicopters played over convoys of sleek limousines.

For the president-elect, it was a day that began with a morning church service and included a luncheon hosted by publishing magnate and former ambassador Walter Annenberg at the F Street Club, as well as a round of meetings with aides and advisers. For many others it was a day of parties and receptions that filled the city's hotel areas with men in formal wear and women in furs.

For thousands of city and area residents, it was a chilly day spent in agonized waiting for stalled traffic to move in the Kennedy Center area, at Dupont Circle, or along 16th Street and Connecticut Avenue. It was also a day of bedazzled staring at the glamour represented by long mink coats and shiny black limousines, as the president-elect and vice president-elect as well as their friends, admires and supporters moved about.

The president-elect had little to say about the hostage negotiations, which appeared for hours yesterday to be in their climactic stages. But as Reagan entered Blair House last night, he told reporters that "I am optimistic."

Today, after private meetings and work on his inaugural address, Reagan is scheduled to attend the Inaugural Gala, which starts at 8 p.m. at the Capital Centre.

An entourage of reporters, Secret Service agents and special D.C. police esort officers followed Reagan's limousine yesterday as it took him and his wife to 9:30 a.m. services at the National Presbyterian Church on Nebraska Avenue in upper Northwest Washington.

The entourage was greeted by about 60 pro-Equal Rights Amendment demonstrators shivering in 23-degree temperatures outside the church. The group, whose members said they were Catholics, Protestants Church Supporters ERA, Why Don't You?"

Among special guests at the church service were Vice President-elect George Bush and his wife Barbara, as well as several cabinet-members-designate and their families. The pastor, the Rev. Louis H. Evans Jr., made no mention of the special guests in his sermon or other remarks.

Many in the congregation said they did not know Reagan was coming until they arrived and saw the police and press outside. "

"It looked like a convention of SWAT teams in the parking lot," said one church member, who complained of the difficulty in getting her child to Sunday School class.

"It was nice of him to come," said one parishioner, but another complained about the demonstrators and difficulty in finding a parking place and said that if yesterday's scene was repeated every Sunday "I think we'll find another church."

Later in the day, a handful of city residents carried picket signs and also voiced dissatisfaction with traffic congestion as they stood in front of the Sheraton Washington Hotel where a heavily attended Governor's reception was being held in connection with the inauguration.

As Army, Navy and Marine Corps bands provided a musical backdrop inside, hundreds of guests trooped past the pickets into the hotel for the reception in which D.C. Mayor Marion Barry participated.

For $10, considerably cheaper than the cost of admission to other inaugural events, but which did not include food or alcoholic beverages, guests were afforded the opportunity to shake the hands of favorite governors.

Later in the afternoon, about 900 persons gathered at the National City Christian Church on Thomas Circle NW downtown for an unusually inclusive worship service that was billed as the only religious service authorized by the official inaugural committee.

Prayers for Reagan, who is to take the oath of office as the nation's 40th president at noon Tuesday, were said in Hebrew, Arabic and English by a variety od clergymen. The Rev. Jerry Falwell, head of the Moral Majority reportedly was scheduled to give the benediction, but did not appear.

At the Kennedy Center last night the Reagans attended a concert of chamber music, a concert given by the National Symphony and a program that included ballet performance. In visits backstage they shook hands with a number of the scheduled performers including pianist Eugene Istomin, ballet star Mikhail Baryshnikov and Mstislav Rostropovich, musical director of the symphony.

Meanwhile, traffic in the Foggy Bottom area was backed up for blocks around the Kennedy Center, merely oozing along when it managed to move at all.

Despite such hardships many people were clearly having a good time. Outside the Capital Hilton Hotel last night a squadron of motorcycle police led the vice president-elect to a gathering.After he entered, two fur-coated women photographed a third standing alongside one of the helmeted officers as he bestrode his machine and grinned broadly.