Show all work for full credit. An 8.5 kg block on a frictionless surface starts
ID: 3160772 • Letter: S
Question
Show all work for full credit.
An 8.5 kg block on a frictionless surface starts at rest inside a spring loaded launcher (point A). The spring is compressed 45 cm and the spring constant of the spring is 580 N/m. The spring is released and the block slides out of the launcher and along the surface (point B). At a point C, the surface of the floor is no longer frictionless but has a coefficient of kinetic friction of 0.33. As the block slides across this surface, it eventually comes to a stop.
a) What is the initial energy stored in the spring at point A?
b) What is the block’s speed at point B?
c) How far from point C does the block come to a stop?
Explanation / Answer
a) potential energy of spring
1/2 k x2 =1/2 x580 x.452 =58.725 J
b)
potential energy = kinetic energy
58.725 = 1/2 m v2
v =3.71 m/s
c) frictional work = kinetic energy
u x 8.5 x9.8 x s = 58.75
s = 2.13 m