The latest Israeli air attack destroyed a metal foundry and a wood workshop that Hamas militants had gathered near, Palestinian witnesses and a Hamas spokesman said.
There were no immediate reports of casualties.
Thirteen Qassam model rockets were fired at Israel by Palestinian fighters in Gaza on Monday, according to Micky Rosenfeld, a spokesman for Israel's police.
Most of the rockets that landed in Sderot caused little or no damage, according to Israeli police.
Islamic Jihad and Hamas both claimed responsibility for the attacks.
David Baker, an Israeli official, said: "Israel is fully determined and fully prepared to take to the necessary actions to bring the Qassam attacks to an end."
The rocket attack on the car came during a meeting in Sderot between Tzipi Livni, Israel's foreign minister, and Javier Solana, foreign policy chief of the EU.
Israel has increased military operations inside Gaza in the wake of renewed Palestinian rocket attacks over the last week.
On Monday, four members of Islamic Jihad men were killed in an Israeli air raid, with a separate air attack killing a Hamas fighter, the Israeli army said.
At least 40 Palestinians have been killed in the Israeli raids.