The tendency of an object to resist change in its state of motion

What is the temperature in degrees celsius of a substance with a tempature of 49k

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

An electron in an x-ray machine is accelerated through a potential difference of 1.00 × 104 v before it hits the target. what is the kinetic energy of the electron in electron volts?