Which statement about motor development is true?
a. motor skills are interrelated. "
b. motor skills are separate, innate abilities. "
c. children acquire motor skills on a fixed maturational timetable.
d. children acquire motor skills in the sequence implied by motor norms.

Aparticle of mass m is projected with an initial velocity v0 in a direction making an angle α with the horizontal level ground as shown in the figure. the motion of the particle occurs under a uniform gravitational field g pointing downward. (a) write down the lagrangian of the system by using the cartesian coordinates (x, y). (b) is there any cyclic coordinate(s). if so, interpret it (them) physically. (c) find the euler-lagrange equations. find at least one constant of motion. (d) solve the differential equation in part (c) and obtain x and y coordinates of the projectile as a function of time. (e) construct the hamiltonian of the system, h, and write down the hamilton’s equations (canonical equations) of motion.

2kg of refrigerant 134a undergoes a polytropic process in a piston-cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80 degree c. a)determine the work for the process in kj. b)sketch the process on a p-v diagram.

Atruck with 34-in.-diameter wheels is traveling at 55 mi/h. find the angular speed of the wheels in rad/min, *hint convert miles to inches & hours to minutes: