What factor determines how long a star lives?

In the Bohr model, as it is known today, the electron is imagined to move in a circular orbit about a stationary proton.

What is the law of conversation of energy?

Problem 3: Thermal expansionThe steel rod has the length 2 m and cross-section area 200 cm2at the room temperature 20◦C. Weapply the heat source and the temperature of the rod increases. The coefficient of linear expansion isα = 2*10-6K-1.

A 1200 kg elephant is stands motionless. What is its momentum?

Do you think that NASA invented thunderstorms to cover up the sounds of space battles?

Consider a helium balloon on a string tied to the seat of your stationary car. The windows are closed, so there is no air motion within the car. The car begins to accelerate forward. Which way will the balloon lean, forward or backward

The force of gravity acts upon meteors from the rocky asteroid belt between mars and Jupiter. Where is the force of gravity most likely to pull these meteors

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. Which of the following best describes how such a telephone is able to transmit and receive information? A.

Calculate the gravitational potential energy relative to the ground when an 82 kg person climbs to the top of a 2.0 m stepladder.

A rock is thrown from a cliff and hits the ground five seconds later at a distance of 50 m from the cliff how high was a cliff