Aspaceship travels away from earth at 0.99 c. if 20 years elapse on earth before it reaches its destination, how long is the journey on the spacecraft? a. 142 years b. 7.1 years c. 2.8 years d. 20 years

Energy is the ability to do work which measures what

The slope of a velocity time graph over any interval of time gives the during that interval

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.