The activity of a sample of caesium-137 is initially 40 kBq. How long will it take for the activity of the sample to fall by 30 kBq? (The half-life of caesium is approximately 30 years.)

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied.

Which statements describe the movement of ocean currents around the globe? check all that apply. strong winds force warm water to sink to the ocean floor. the coriolis effect causes warm and cold water to mix. cool dense water sinks to the ocean floor. warm water replaces cool surface water. wind blowing parallel to the shore causes upwelling of cool water.

What properties of a moving object are used in determining the object's energy of motion