how many turns are required in a 5.0 cm solenoid with 9.81 A flowing through it to generate a magnetic field of 2.0 x 10^-2 T in its core?

Does anyone have the answers to online physics course plato course physics, semester a v3.0

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration

The particle p starts from rest at point a at time t = 0 and changes its speed thereafter at a constant rate of 2.8g as it follows the horizontal path shown. determine the magnitude and direction of its total acceleration (a) just before point b, (b) just after point b, and (c) as it passes point c. state your directions relative to the x-axis shown (ccw positive) and choose the angle with the smallest magnitude.