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A 1.22 kg block slides on a frictionless, horizontal surface with an speed of 1.

ID: 1377424 • Letter: A

Question

A 1.22 kg block slides on a frictionless, horizontal surface with an speed of 1.35 m/sec. The block encounters an unstretched spring with a spring constant of 280 N/m.

1)

What is the initial kinetic energy of the block before it hits the spring?

KE0 =

J  

2)

What is the potential energy of the mass and spring system when the spring is at its point of maximum compression?

Umax =

J  

3)

How far is the spring compress before the block comes to rest?

A =

meters  

4)

If the mass and block were to oscillate, what would be the period of the oscillation?

T =

seconds  

5)

How long is the block in contact with the spring before it comes to rest?

t =

seconds  

Explanation / Answer

1) KEo = 0.5*m*uo^2

= 0.5*1.22*1.35^2

= 1.11 J

2) Apply conservation of Enrgy

Umax = KEo

= 1.11 J

3) Umax = 0.5*k*A^2

==> A = sqrt(2*Umax/k)

= sqrt(2*1.11/280)

= 0.089 m

4) angular frequency, w = sqrt(k/m)    (kg/s^2)

= sqrt(280/1.22)

= 15.15 rad/s

time periode, T = 2*pi/w

= 2*pi/15.15

= 0.414 s

5) the block in contact with the spring before it comes to rest,

t = T/4

= 0.414/4

= 0.103 s