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please show all work 2. In the shown below, a 540 g box is placed in front of a

ID: 1438761 • Letter: P

Question

please show all work

2. In the shown below, a 540 g box is placed in front of a spring, with spring constant k, that is compressed figure a distance Ar 18.1 cm from its natural length. When the box is let go. the spring will push the box and it The will slide up the frictionless hill of height H 1.7 m. At the top of the hill, the ground is not frictionless. coefficient of kinetic friction in this area is 0.15 and the coefficient of static friction 0.25. The box will travel a distance d 7.0 cm on the rough surface at the top of the hill before coming to a stop. Fnction on this surface (a) (5 points) hat is the total work that friction does in bringing the box to a stop? (b) (2 points) Before entering the area with friction what is the kinetic energy of the box? c) (3 points) What is the total mechanical (potential plus kinetic) energy of the box at the top of the hill (d) (2 points) What is the total mechanical energy at the bottom of the hill (after leaving the spring)? (e) (2 points) How much potential energy is stored in the spring when it is fully compressed? (f) (5 points) What is the spring constant k for this spring? Page 2

Explanation / Answer

Here,

m = 540 gm = 0.540 Kg

x = 18.1 cm = 0.181 m

H = 1.7 m

uk = 0.15

us = 0.25

d = 0.07 m

a)

Total work done by friction = -uk * m * g * d

Total work done by friction = - 0.15 * 0.54 * 9.8 * 0.07

Total work done by friction = -0.056 J

b)

Kinetic energy of the box = - total work done by friction

Kinetic energy of the box = 0.056 J

the Kinetic energy of the box is 0.056 J

c)

at the top of hill

total mechanical energy of the box = kinetic energy of block + potential energy of block

total mechanical energy of the box = 0.056 + 0.54 * 9.8 * 1.70

total mechanical energy of the box = 9.052 J

d)

as there is no frictional force on the ramp

total mechanical energy of the box at the bottom = total mechanical energy of the box at the top

total mechanical energy of the box at the bottom = 9.052 J