1. A 10 kg brick falls from a height of 2 m. a. Suppose it falls unto a carpet, 1 cm thick. Assuming the force stopping it is constant, find the average force the carpet exerts on the brick. Answer: 2 x 10^4 N b. Now if it falls onto a 5 cm foam rubber pad, what constant force is needed to bring it to rest? Answer: 4 x 10^3 N I know the formula F*/\t =/\p. To get F, /\p//\t. But do these objects have any effects on the brick's displacement and the time interval? [In some of these problems, kinematic formulas are needed to find things that are not given besides what one seeks. I used v_f^2 = V_i^2 + 2a/\x to find the velocity (about 63 m/s) if there was no object on the ground.] Please tell me the steps to get the force. 2. A 7600-kg space probe is traveling through space at 120 m/s. Mission control determines that a change in course of 30 degrees is necessary and, by electric communication, instructs the probe to fire rockets perpendicular to its present direction of motion. If the escaping gas leaves the craft's rockets at an average speed of 3200 m/s, what mass of gas should be expelled? Answer: 170 kg No one, not even the instructor, could figure out how to do this. 60-90-30 triangles, x and y components, and other momentum formulas were used but to no avail. How do you do this? Thank you for any clues!