A2.0 kg wood block is launched up a wooden ramp that is inclined at a 27 ∘ angle. the block's initial speed is 13 m/s . the coefficient of kinetic friction of wood on wood is μk=0.200. you may want to review (page 131) . for with math skills, you may want to review: vector components part a what vertical height does the block reach above its starting point? express your answer to two significant figures and include the appropriate units. view available hint(s) hh = nothing nothing part b what speed does it have when it slides back down to its starting point? express your answer to two significant figures and include the appropriate units. view available hint(s) vv = nothing nothing provide feedback

a)

m

b)

ms⁻¹

Explanation:

= mass of the wood block = 2 kg

= initial speed of the block at the bottom = 13 m/s

= angle of incline = 27°

= Coefficient of kinetic friction = 0.2

= kinetic frictional force

= height of the incline gained

= length of the incline traveled

In triangle ABC

= Normal force on the block by incline surface

From the force diagram of the block, force equation perpendicular to the incline surface is given as

                           Eq-1

kinetic frictional force on the block is given as

Using Eq-1

Work done by kinetic frictional force is given as

Using conservation of energy

Kinetic energy at the bottom = work done by frictional force + potential energy at the top

inserting the values

m

b)

= final speed of the block after returning to starting point

Using conservation of energy

Kinetic energy at the bottom initially = work done by frictional force + Kinetic energy at the bottom finally

inserting the values

ms⁻¹

as a general rule, scissors have blades less than 6 in (15 cm) long and usually have handles with finger holes of the same size. shears have blades scissors used to cut hair or fabric must be much sharper.