Analysis of a basalt rock sample shows that 25% of its radioactive K-40 remained undecayed. How old is the basalt? A) 2.6 billion years
4.6 billion years
B) 1.3 billion years
D) 3.9 billion years

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

What would be the strength of earth's gravitational field at a point where an 80.0 kg astronaut would experience a 80% reduction in weight

What is the kinetic energy of a baseball moving at a speed of 40 m/s if the baseball has mass of 0.15 kg?