What must occur for work to be done on an object?

a. a force must hold the object in place.
b. force must be applied in a direction opposite to the motion of the object.
c. no net force should be applied to the object.
d. the object must move.

A2.00-m long piano wire with a mass per unit length of 12.0 g/m is under a tension of 8.00 kn. what is the frequency of the fundamental mode of vibration of this wire?

A0.750 kg aluminum pan is removed from the stove and plunged into a sink filled with 10.0 kg of water at 293 k. the water temperature quickly rises to 297 k. what was the initial temperature of the aluminum pan? the specific heat of aluminum is ca = 900 j/(kgk) and water is cw = 4190 j/(kgk)

What is the relationship between the direction of motion of the balloon and the wind currents