PLEASE HELP ME QUICK. NEWTON'S LAWS

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

Aquantity of gas has a volume of 1.5 m3 and an absolute pressure of 95 kpa. when the gas is compressed to a volume of 0.5 m3, what is the new absolute pressure of the gas? (assume that there’s no change in temperature.)

Using the work energy theorem. what is the velocity of a 850kg car after starting at rest when 13,000j of work is done to it.