What is the mass of a football player who weighs 1250 n.?

Is the alien theory a scientific claim? why or why not? just took the test it was , : " the alien theory is not a scientific claim because it is not based on valid data, there is no evidence to support it, and it does not come from a reliable source."

Arod of some material 0.20 m long elongates 0.20 mm on heating from 21 to 120°c. determine the value of the linear coefficient of thermal expansion [in (degrees c)^-1] for this material.

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?