There is a small ball connected to a light spring, which makes a simple harmonic vibration with amplitude A along the x-axis, and its expression is expressed by a cosine function. If t = 0, the motion state of the ball is:
(1) x。= -A
(2) The overbalance position moves in the positive x direction
(3) Move to the negative direction of x at x = A / 2
(4) After x = A / radical2, move to the positive direction of x.
Use the vector diagram method to determine the value of the corresponding primary phase and write the vibration expression.

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 790 n/m. it is initially at rest on an inclined plane that is at an angle of 28 degrees with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is k = 0.14. in the initial position, where the spring is compressed by a distance of a = 0.18 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Which fact supports the conclusion that there will be fewer farm managers in the future? a) a farmer manager’s duties vary by the type of farm. b) farm technology is replacing some administrative jobs c) farm managers often need experience but not education. d) administrative duties include budgeting and training staff.

Auniform crate c with mass mc is being transported to the left by a forklift with a constant speed v1. what is the magnitude of the angular momentum of the crate about point a, that is, the point of contact between the front tire of the forklift and the ground