An insulated beaker with negligible mass contains liquid water with a mass of 0.250 kg and a temperature of 84.4 ∘c .
how much ice at a temperature of -10.6 ∘c must be dropped into the water so that the final temperature of the system will be 21.0 ∘c ?
take the specific heat of liquid water to be 4190 j/kg⋅k , the specific heat of ice to be 2100 j/kg⋅k , and the heat of fusion for water to be 3.34×10^5 j/kg .

How many seconds does it take a pebble released from rest off a bridge to fall 29.4 m ? what is the pebble's speed when it has fallen 29.4 m ?

Determine the fraction of the magnitude of kinetic energy lost by a neutron (m1 = 1.01 u) when it collides head-on and elastically with a target particle at rest which is 21h (heavy hydrogen, m = 2.01 u).

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.