A15 kg bullet leaves the 30 cm long barrel of a gun at a speed of 240 m/s.
a. find the exit velocity of the bullet.
b. find the average force exerted on the bullet by the expanding gases as the bullet moves through the length of the 30 cm barrel

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?

Two 1.20-m nonconducting wires meet at a right angle. one segment carries + 2.50 µc of charge distributed uniformly along its length, and the other carries - 2.50 µc distributed uniformly along it, as shown in fig. 21.50. ( a. find the magnitude and direction of the electric field these wires produce at point p, which is 60.0 cm from each wire. ( b. if an electron is released at p, what are the magnitude and direction of the net force that these wires exert on it?

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?