When starting a heavy train, why will train engineers sometimes back up, stop, and then proceed forward? (This technique is called "bunching slack.")

A Ping-Pong ball has a diameter of 1.99 cm and average density of 0.121 g/cm3. What force would be required to hold it completely submerged under water? The acceleration of gravity is 9.8 m/s 2. Answer in units of N.

What do glaciers and landslides tend to create

What is the name of moving fields of angular blocks which are formed by gravity and the freezing-thawing cycle? A. Scree B. Talus C. Bedrock slumps D. Bedrock slides E. Rock glaciers

What is the difference between speed and velocity? A) velocity describes speed with direction. B) there is no difference. C) Velocity describes direction with position. D) Velocity is used in space, while speed is used on earth.

If the mass of a material is 46 grams and the volume of the material is 14 cm^3, what would the density of the material be?

Race car drivers must slow down as they make turns on the track. This is best explained by the law of inertia. Which statement best describes inertia for the car going around a turn? A) A body in motion stays in motion at the same speed.

What is is the ratio of the distance over which the force is applied to the distance over which the load is moved

What factor can increase the potential energy of an object? A Decrease in speed B Decrease in density C Increase in temperature D Increase in height from the ground?

Microwave ovens emit microwave energy with a wavelength of 12.3 cm. What is the energy of exactly one photon of this microwave radiation?

When light bounces off a surface, which component will be reflected more - the component that is parallel to the surface, or the component that is perpendicular to the surface, and why?