A student makes some observations about three solids and summarizes the results in the table below.
Mass
3.08
Solid 1
Solid 2
Solid 3
Melting Point
776°C
445°C
445°C
Color
white
white
3.0 g
9.8 g
white
Could any of the solids be the same substance and why?
Solids 1 and 2 could be the same substance. Even though they do not have the
same melting point, they have the same mass.
Solids 2 and 3 could be the same substance. Even though they do not have
the same mass, they have the same melting point and color.
Solids 1, 2, and 3 could all be the same substance. Even though they do not all
have the same mass and melting point, they have the same color.
Solids 1, 2, and 3 cannot be the same substance because they have different
combinations of color, melting point, and mass.

Amass m = 74 kg slides on a frictionless track that has a drop, followed by a loop-the-loop with radius r = 18.4 m and finally a flat straight section at the same height as the center of the loop (18.4 m off the ground). since the mass would not make it around the loop if released from the height of the top of the loop (do you know why? ) it must be released above the top of the loop-the-loop height. (assume the mass never leaves the smooth track at any point on its path.) 1. what is the minimum speed the block must have at the top of the loop to make it around the loop-the-loop without leaving the track? 2. what height above the ground must the mass begin to make it around the loop-the-loop? 3. if the mass has just enough speed to make it around the loop without leaving the track, what will its speed be at the bottom of the loop? 4. if the mass has just enough speed to make it around the loop without leaving the track, what is its speed at the final flat level (18.4 m off the ground)? 5. now a spring with spring constant k = 15600 n/m is used on the final flat surface to stop the mass. how far does the spring compress?