Exercise 4: A light string ABCDE whose extremity A is fixed, has weights \( \mathrm{W}_{1} \) and \( \mathrm{W}_{2} \) attached to it at B and C . it passes round a small smooth peg at D carrying a weight of 300 N at the free end E as shown. If in the equilibrium position, BC is horizontal and AB and CD make \( 150^{\circ} \) and \( 120^{\circ} \) with BC . Find (a) tensions \( \mathrm{AB}, \mathrm{BC} \) and CD for the string and (b) magnitudes of \( \mathrm{W}_{1} \) and \( \mathrm{W}_{2} \)

HW 1: Name Clarabelle Barraza student ID: 1. In major league baseball, the pitcher's mound is 60 feet from the batter. If a pitcher throws an \( 85 \mathrm{~m} / \mathrm{h} \) fastball, how much time elapses from when the ball leaves the pitcher's hand until the ball reaches the batter? Solve it in the unit of second.

Nuclear fission and nuclear fusion are important nuclear processes that result in a change in the nucleus of isotopes. (a) Compare nuclear fission and nuclear fusion, and explain two similarities be- tween them. (b) Describe two ways nuclear fission and nuclear fusion differ regarding require- ments for reactions and applications. You can start your response with: - Nuclear fission and nuclear fusion are similar in that they both ... - Two ways in which nuclear fusion differs from nuclear fission are...

What requirements must be met for a nuclear fu- sion reaction to occur? A select all that apply. A extremely low temperatures C extremely high temperatures D a large amount of pressure

What is the force on a 1000 kg elevator that is falling freely at \( 9.8 \mathrm{~m} / \mathrm{sec}^{2} ? \)

Suponha que, neste experimento, os cavalos de Thompson exercessem uma força F, ao mesmo tempo que, a cada segundo, deslocavam uma distância de 3 metros. Se em 1,6 horas, 19 litros de água tiverem sido aquecidos de uma temperatura inicial de \( 20^{\circ} C \) até uma temperatura final de \( 100^{\circ} C \), calcule o valor da força F realizada pelos cavalos. Suponha, para isso, que todo o trabalho realizado pelos cavalos seja convertido em energia térmica da água. Considere que o calor específico da água vale \( c_{a g u a}=1 \) cal \( / g^{\circ} C \), que \( 1 c a l=4,18 \mathrm{~J} \) e que a densidade da água é de \( 1 \mathrm{~g} / \mathrm{mL} \) (ou seja, cada litro corresponde a 1000 g de água).