What is the half life of a radioactive isotope that decreased to one-fourth its original amount in 100 year

If you were traveling away from Earth at speed 0.5c, would you notice a change in your heartbeat? Would your mass, height, or waistline change? What would observers on Earth using telescopes say about you?

What acceleration is produced by a force of 2000 N and 1000 kilogram car

Einstein's general theory of relativity made or allowed us to make predictions about the outcome of several experiments that had not yet been carried out at the time the theory was first published.

A stone is thrown upward from the top of a building at an angle of 30.0° to the horizontal and with an initial speed of 20.0 m/s, the height of the building is 45.0 m. How long is the stone in flight?

What physical properties of nylon and leather make them good materials to use for shoelaces? A. high density and low conductivity B. durability and flexibility C. hardness and durability D. low viscosity and flexibility

What is the conversion of celcius to kelvin?

Why does the percentage of water vapor vary?

A situation that restricts something

Why is the sky blue all the time

Where did the rotational kinetic energy of the earth come from?