A0.095-kg aluminium sphere is dropped from the roof of a 55-m-high building. the specific heat of aluminium is 900 j/kg⋅c∘ .
if 65 % of the thermal energy produced when it hits the ground is absorbed by the sphere, what is its temperature increase?

What happens to atoms and chemical bonds during a reaction?

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?