(a) How much energy is released when an electron and a positron annihilate each other? (b) How much energy is released when a proton and an antiproton annihilate each other?

Two ice skaters, one with a mass of $57 \mathrm{~kg}$ and the other with a mass of $75 \mathrm{~kg}$, stand facing each other on the surface of a frozen pond. One of the skaters exerts a $135 \mathrm{~N}$ force against the other. Calculate the magnitude of the acceleration of each skater.

Standing on Earth, gravity exerts a downward force on you, yet you don't fall toward the center of the planet. a. Name the other force that acts on you and keeps you in equilibrium. b. What is the direction of the other force? c. What do you know about the strength of this other force?

Income redistribution in the United States results in the income share of the ________ rising and the income share of the ________ falling. A. lowest quintile; other four quintiles B. two lowest quintiles; other three quintiles C. three lowest quintiles; other two quintiles D. four lowest quintiles; highest quintile

Prove that the diagonals of a parallelogram bisect each other.

Two protons, each having a speed of $0.985 c$ in the laboratory, are moving toward each other. Determine $(c)$ the momentum of one proton as seen by the other proton.

The following table gives the percent of the market controlled by the most popular Internet browsers in 2016. Sketch or otherwise create an appropriate graph of the distribution and comment on its important features.

The nearest star other than the Sun is about 40 trillion km away. About how many miles away is the nearest star other than the Sun?

Describe the Sun in relationship to other stars in the universe .

Are other isomers of 2-iodobenzoic acid possible?

Helium is an inert gas, which means that it doesn't readily combine with other elements. What five other elements would you also expect to be inert gases?

As the minor and major grooves of the DNA wind around a DNA double helix, do they ever intersect each other, or do they always run parallel to each other?

Income redistribution in the United States results in the income share of the ________ rising and the income share of the ________ falling.

A. lowest quintile; other four quintiles

B. two lowest quintiles; other three quintiles

C. three lowest quintiles; other two quintiles

D. four lowest quintiles; highest quintile

Relate the torque $T$ to the other variables shown.