As the wheels of a train move along the train tracks, what type of friction exists between the wheels and the tracks

Aball with a mass of 275 g is dropped from rest, hits the floor and rebounds upward. if the ball hits the floor with a speed of 2.40 m/s and rebounds with a speed of 1.70 m/s, determine the following. (a) magnitude of the change in the ball's momentum (let up be in the positive direction.)

Freya has a mass of 14kg she is running at 1.1m/s to the left when she runs into eric, who is standing still. eric has a mass of 18kg. after the collision, they continue moving together. what is their velocity after the collision. a. 0.48 m/s to the leftb. 2.5 m/s to the leftc. 0.86 m/s to the leftd. 1.4 m/s to the left

5volt is supplied to an electrical circuit.if the resistance of the circuit is 2.5ohms ,calculate the current flowing through the circuit.