25. A net force of magnitude 36 N gives a mass mi an acceleration of magnitude 4.0 m/s2. The same net force gives another mass ma an acceleration of 12 m/s2. What magnitude of acceleration will this net force give to the entire mass if mi and ma are fastened together? 26. In an electric tube, an electron of mass 9.1x10-31 kg experiences a net force of magnitude 8.0x1015 N over a distance of 2.0 cm. a) Calculate the magnitude of the electron's acceleration. b) Assuming it started from rest, how fast would the electron be moving at the end of the 2.0 cm motion? 27. A 1.2x104 kg truck is traveling South as 22 m/s. a) What net force is required to bring the truck to a stop in 330 m? b) What is the cause of this net force? 28. Calculate the acceleration of the cart on a table top as shown below, given the following assumptions: a) No friction is acting on the cart. b) A frictional resistance of magnitude 2.0 N is acting on the cart. m = 4.0 kg frictionless pulley m = 2.0 kg 29. A 2.00 x 102 kg motorcycle accelerates from 20.0 m/s to 50.0 m/s in 5.0 s. The unbalanced force on the motorcycle is [all directions are south] (B) 1.20 x 103 N (C) 3.33 x 10' N (A) 4.00 x 103 N (D) 3.00 x 10-2 N (E) 6.0 x 103 N 30. The property of matter described in Newton's first law of motion is: (E) velocity (A) inertia (B) gravity (C) weight (D) acceleration 31. When a rock is thrown straight into the air what is its acceleration at the top of its flight when its instantaneous velocity is zero? e table below