3.A bridge usually has expansion joints. They allow the bridge to become slightly longer when it experiences thermal expansion. Look at the diagram below of the bridge joint. When the weather
becomes cool, the "teeth" of the joint move away from each other. When the weather becomes
warm, they move toward each other. Which statement is true about the particles that make up the
bridge?
A. When the sides of the joint are close together, the particles have more kinetic energy
than they do when the sides are farther apart.
B. When the sides of the joint are far apart, the particles have more kinetic energy than
they do when the sides are closer together.
C. The particles contain the same amount of kinetic energy no matter how much the
bridge has expanded.
D. The kinetic energy of the particles changes, but the amount it changes does not
depend on the temperature of the bridge.

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?

You want to lose weight and have been trying to decide which type of fad diet is best for you. you ask your doctor, who responds that a. fad diets are a temporary fix but generally don't have any side effects b. fad diets can be used several times a year to maintain a healthy weight c. fad diets can be risky for your health and, in the long run, do not work d. fad diets should never be used one right after the other; there should be a break between them select the best answer from the choices provided. a b c d

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?