Real springs have mass. How will the true period and frequency of a simple harmonic oscillator (SHO) on the end of the spring be affected compared to that for a SHO oscillating on the end of an idealized massless spring? Explain.

A clock uses a pendulum supported on a long, thin brass rod. If it is accurate at 20 degree Celscius, explain whether it will run fast or slow on a hot day (32 degree Celscuis)?

A bowling ball is hung from the ceiling by a steel wire. The instructor pulls the ball back and stands against the wall with the ball against his nose. To avoid injury the instructor is supposed to release the ball without pushing it. Explain why.

Mammals that depend on being able to run fast have slender lower legs with flesh and muscle concentrated high, close to the body. On the basis of rotational dynamics, explain why this distribution of mass is advantageous.

# Rotating Wheel

There are a few factors that will determine the rotation of a rigid body. Considering the purpose for which it is created, explain briefly why the handrim that the basketball players grab is almost as big as the wheel itself. Or you may like to comment on why this is not the case for the racers.

# Crash Cushions

A crash cushion system like the one shown below installed on the highway may consist of a series of boxes containing sand or water, lined up and supported by a steel framework. During a crash, the boxes burst one by one, serving as a series of cushions to absorb the energy of collision. Explain how this may help in preventing serious damage to the vehicle.

# Glass Jar

You may notice that sometimes it is difficult to open the metal lid that is tightly wound over a glass jar. Now that you have learned that different substances expand at a different rate, explain how you would open the metal lid and the physics behind.

# Tiled vs Carpeted Floors

Different types of floorings feel different to our feet. Why do tiled floors feel cooler to the feet than carpeted floors? What about a wooden flooring?

# Bungee Ride

Energy transformations take place all the time and all around us, from a ride on the roller coaster to warming ourselves near a fire started in the open air. In a game of bungee ride, explain briefly what kind of energy changes take place.

# Water Balloons

In a game of water balloons, participants catch as many water balloons thrown to them as possible. What is the best way to catch a water balloon without bursting it? Explain any physics behind your reasoning.