The half-life for a 400-gram sample of radioactive element X is 3 days. How much of element X remains after 15 days have passed? A.
12.5 g

B.
25 g

C.
50 g

D.
100 g

Shelly experiences a backward jolt when the driver starts the school bus. which of the following explains this phenomenon? a. the inertia of shelly b. the inertia of the bus c. the normal force of the seats on shelly d. the net force acting on shelly in a backward direction e. a zero net force acting on shelly

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?

If forces acting on an object are unbalanced. true or false