You wish to move a heavy box on a rough floor. the coefficient of kinetic friction between the box and the floor is 0.9. what is the best way to reduce the force of friction between the box and the floor while the box is moving? a. push or pull the box with a force parallel to the floor. b. pull the box with a force directed up at an angle of 30â° from the horizontal. c. push the box with a force directed down at an angle of 30â° from the horizontal. d. the coefficient of friction does not change so the force of kinetic friction acting on the block must be constant e. both b and c result in the same force of friction.

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon

State the below theories and give the name of the writer of the theory 1. wave theory 2. quantum theory 3. corpuscular theory 4. electromagnetic theory

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 740 n/m. it is initially at rest on an inclined plane that is at an angle of theta= 26 with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is uk = 0.17. in the initial position, where the spring is compressed by a distance of d = 0.16 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. the block's initial mechanical energy is 9.472 j. 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.