How do we know what goes on under the surface of the Sun?
a. We have X-ray images from satellites of the interior of the Sun.
b. Astronomers create mathematical models that use the laws of physics, the Sun's observed composition and mass, and computers to predict internal conditions.
c. We have sent probes below the surface of the Sun.
d. By measuring Doppler shifts, we observe vibrations of the Sun's surface that are created deep within the Sun.

Explain vector addition, triangle method and parallelogram method

You and a friend (alex) are at a a tree-top adventure park .. . part of the course requires you to climb up a rope. you both climb the same rope in the same amount of time. however, the tension in the rope is greater when alex climbs. who did the most work? alex did - more tension means more force - more force means more work was done you did - less tension means less force - less force means more work was done to find the work done, the force exerted and distance moved are multiplied. a couch is moved twice before you are happy with its placement. the same force was used to move the couch both times. if more work is done the first time it is moved, what do you know about the distance it was moved? when more work was done, the couch was moved less. when more work was done, the couch was moved further. when more work was done, the couch wasn't moved at all. when more work was done, the couch was moved the same distance.

Abucket full of water weights 4 kg and water well is 10m deep. a girl draws water from the well. it takes the girl 3 minutes to draw a bucket full of water from the well. what is the power of the girl?