15. If y = 3x-4x+2 then slope at x = 1 is: (1) 1 (2) 2 (3) 4 (4) -2 16. sin240 = ? (1) - 2 (3) 3 1/2 17. Value of sin 2 is (4) (2) 12 (1) 23 (2) (3) 90 180 (4) 0 18. The rate of mass of the gas emitted from rear of a rocket is initially 0.1 kg/sec. If the speed of the gas relative to the rocket is 50 m/sec and mass of the rocket is 2 kg, then the acceleration of the rocket (in m/sec) is :- [Gravity free space] (1) 5 (2) 5.2 (3) 2.5 (4) 25