Some ringtones for mobile phones can only be heard by young people. What is the likely frequency of these ringtones? a. 250 Hz
b. 5,000 Hz
c. 10,000 Hz
d. 17,000 Hz​

Molten iron fills a mould, which has a volume of 200 cm cubed. calculate the volume when the iron cools and solidifies.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?