At time t = 0 s, an object is observed at x = 0 m; and its position along the x-axis follows this expression: x = –4t + t2, where the units for distance and time are meters and seconds, respectively. what is the object's displacement between t = 1.0 s and t = 3.0 s?

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?

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?

By what factor does the drag force on a car increase as it goes from 65 to 110 km/h?