4. This is the same as both situations above

5. Springs and Hooke’s Law
k is the “force constant”

6. Springs and Hooke’s Law
k is the “force constant”

7. Springs and Hooke’s Law
A 1.3 kg mass is attached to a spring with force constant k = 95 N/m. It sits on a surface with a coefficient of kinetic friction mk = It is then pulled away from equilibrium to x = 18 cm and released from rest. What is its initial acceleration?

8. If the sum of all the external forces acting on an object is zero, then…
A) The object must not be moving
B) The object must be moving at a constant velocity
C) The object may be either at rest or moving with constant velocity
D) The velocity graph will have a constant, non-zero slope
E) The object may be either at rest, moving with constant velocity, or moving with constant positive acceleration.

9. Translational Equilibrium
No accelerations  The sum of all external forces is zero

10. Translational Equilibrium
A man lifts a bucket from a well at a constant speed by pulling down on rope draped over a pulley.
The bucket’s mass is m and it is rising at a constant speed v.
What is the tension T1 in the rope?
What is the tension T2 in the chain supporting the pulley?

11. In case (2), is the tension:
a) greater than,
b) less than, or
c) equal to
the tension in case (1)?

13. To hang a 6.20 kg pot of flowers, a gardener uses two wires – one attached horizontally to a wall, the other sloping upward at an angle of 40.0˚ and attached to the ceiling. Find the tension in each wire.