X A worker pushes a crate up a ramp.
Which change to the ramp would be the best way to increase its mechanical
efficiency (ME), and why?
A. Reduce the length of the ramp so that more work is done in less
time.
O B. Wax the sloped surface of the ramp to decrease the friction
between the crate and the ramp.
O C. Cover the ramp with sandpaper to increase the friction between
the crate and the ramp.
D. Reduce the height of the ramp so that less output work is done on
the crate

the small 0.38-kg slider is known to move from position a to position b along the vertical-plane slot. determine (a) the work done on the body by its weight and (b) the work done on the body by the spring. the distance r = 0.70 m, the spring modulus k = 154 n/m, and the unstretched length of the spring is 0.53 m

explanation:

-reverse card

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.

that would be because of both gravity and friction. so     c