What is the rate at which work is done in lifting a 35-kilogram object vertically at a constant speed of 5 meters per second? 1) 1700 w 2) 340 w 3) 180 w 4) 7 w

If the force on an object is in the negative direction, the work it does on the object must be [2 points a) negative. b) positive c) the work could be either positive or negative, depending on the direction the object moves

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.

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?