How much heat must be added to 30.0 g of solid iron to melt it, assuming the iron is already at it's melting point?

The image shows a pendulum in simple harmonic motion the pendulum starts at a and swing to e

Aforce of 9.00 newtons acts at an angle of 19.0 to the horizontal. what is its component in the horizontal direction?

Imagine you are standing in the antarctic during the southern hemisphere summer. the sky is clear and blue. there are no clouds in the sky. your shadow is cast on the icy ground. what is the color of the shadow?