15. A 6.0-kg object, initially at rest in free space, “explodes" into three segments of equal mass. Two of these segments are observed to be moving with equal speeds of 20 m/s with an angle of 60° between their directions of motion. How much kinetic energy is released in this explosion? (a) 2.4 kJ (b) 2.9 kJ (c) 2.0 kJ (d) 3.4 kJ (e) 1.2 kJ

Two blocks with masses m1 = 1.4kg and m2 = 4.6kg are at rest on a frictionless surface with a compressed spring between them. When the blocks are let go, block 1 is observed to have a velocity of 4.4m/s to the left. What is the speed of block 2?

Two balls are about to collide. Ball 1 has a mass of 14kg, and is moving [down] at an unknown speed. Ball 2 is 9kg and is moving [up] at a speed of 12m/s. After they collide, ball 1 moves with a velocity of 10m/s [80° Up of right]. Ball 2 moves with an unknown velocity [60° down of left]. An image has been added to help picture the situation. What is the initial velocity of ball 1?

Our brave astronaut Ms. Rose Noneck is at rest spacewalking 9.3 m away from her spaceship when her jetpack runs out of electricity (powered by TCC?). And worst – she is down to 60 seconds of oxygen left – there's plenty in her spaceship as well as her delicious lunch of baba ganoush. She remembers Prof. P's class and throws her 23.6 kg jetpack in the opposite direction of her spaceship at 1.4 m/s. Her mass is 55 kg. Will she make it back to her spaceship before she runs out of air? Convince me with numbers - tell me how long in seconds it takes for her to get back. Will we be seeing her in Exam 4? Or is it the end for her?