A child is playing with a toy car, and it accelerates to the south from 1.2m/s to 6.3m/s. if the toy car's acceleration is 2.75m/s2, what is the amount of time that the child takes to accelerate the car? Show all your work.

Aspring has a natural length of 8 m. if a 12-n force is required to keep it stretched to a length of 10 m, how much work w is required to stretch it from 8 m to 16 m? (round your answer to two decimal places.)

What is the power rating of the lightbulb if 3.0 a flow through it when connected to a 15 v battery

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.