The power needed to accelerate a projectile from rest to its launch speed v in a time t is 42.0 w. how much power is needed to accelerate the same projectile from rest to a launch speed of 2v in a time of t?

From center station, a train departs every 30 minutes on the fast line and a train departs every 50 minutes on the state line. if two trains depart from center station at 8: 00 a. m., one on each of the two lines, what is the next time that two trains, one on each line, will depart at the same time?

If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the refrigerator if it released 380j of energy to the room?

Assume you measured the mass of the cart to be (500 ± 1) g and the mass of the additional mass you put on the cart to be (500 ± 1) g as well. since the scale you are using in the lab cannot measure objects heavier than 600g you will have to sum up individual pieces and propagate the error. so what would be the mass and the standard error of the cart and the mass