'A 0.04 kg toy is attached to a 2 meter string that can swing without air resistance from a fixed point. It was brought to a angle 0, as shown, where cos 0 = 0.9
12 m
0 0.04 kg
If the toy is released from rest, it will swing with a maximum amplitude of e.
Calculate its maximum speed.

Determine the age of a fossil if it had only one eighth of its original carbon-14 content remaining?

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?