4. Balok A bermassa 3M dihubungkan dengan tali ringan melalui katrol yang licin ke balok B bermassa M. Pada keadaan awal, balok Aditahan sehingga berada pada ketinggian h
diatas balok B yang terletak di lantai. Sesaat kemudian balok A dilepaskan. Jika g adalah
percepatan gravitasi setempat, tentukanlah kecepatan balok B saat berpasasan dengan
balok A​

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

According to the image below, which season is about to begin in the southern hemisphere? a. summer b. autumn c. winter d. spring