Question

PHY 121 Homework 12 Due: Thursday, November 21" Physics 121 Homework 12 1) You are riding a bike at a speed of 4.3 m/s. You apply the rear brakes and come to a stop in 4 seconds. The moment of inertia of the rear bike wheel is 0.15 kg.m', and its radius is 0.33 m. If the rear wheel is rolling without slipping, what was the average torque exerted on it during the 4 seconds that you applied the brakes? (7 points) 2) A light bulb filament is made of tungsten. It has a cross sectional area of 1.7 x 10 m' and a length of 0.02 m. What tension force should you apply to the filament to stretch it by the diameter of I tungsten atom, which is 2.1 x 10-10 m? The Young's modulus for tungsten is 3.6 x 1011 N/m°. (4 points) 3) The pressure in the core of Jupiter is about 4.8 x 10" Pa. At this pressure, water will not stay in liquid form, but if it did, what would its density be? The bulk modulus of water is 2.2 x 10 N/m'. (4 points)

Answer 1

M-4.3ms o 4 3 075 a- v-u 3.25t Sto 6.33 O- 488 Nm O.1S x 3.25 T - Scanned with CS CamScanner