A 5 kg watermelon is pushed across a table by Gail. Gail applies a force of 30 N to the right. If the acceleration of the watermelon is 4 m/s/s to the right, what is the force of friction acting on the watermelon?

What would be the strength of earth's gravitational field at a point where an 80.0 kg astronaut would experience a 80% reduction in weight

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.

The force it would take to accelerate an 900-kg car at the rate of 6m/s2