An electric elevator with a motor at the top has a multistrand cable weighing 7 lb divided by ft. when the car is at the first floor, 160 ft of cable are paid out, and effectively 0 ft are out when the car is at the top floor. how much work does the motor do just lifting the cable when it takes the car from the first floor to the top?

Which of the following quantities are units of momentum? (there could be more than one correct choice.) a)n m b) kg s/m c) kg m/'s d)n-s 12 points] e) kg m2/s2

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.

You have a pick-up truck that weighed 4,000 pounds when it was new. you are modifying it to increase its ground clearance. when you are finished