Suppose an elephant has a mass of 2750 kg. 1) How fast, in meters per second, does the elephant need to move to have the same kinetic energy as a 69.5-kg sprinter running at 8.5 m/s?

How fast would a 30-kg kid need to run in order to have the same kinetic energy as an 8.0-g bullet fired at 400 m/s, in m/s? Your answer needs to have 2 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.

If a sprinter running at a speed of 10 meters per second could convert his/her kinetic energy into upward motion, how high could he/she jump? h = (10 m/s)^2 / (2 * 9.80 m/s^2) = 5.102 m. (Why do we multiply 2 * 9.80 in this equation?) Im trying to figure out why we multiply 2 times 9.8

The driver of a 760.0 kg car decides to double the speed from 21.1 m/s to 42.2 m/s. What effect would this have on the amount of work required to stop the car, that is, on the kinetic energy of the car? KE x 105 J KE = × 105 J (select) v times as much work must be done to stop the car.

A 72 kg student traveling in a car with a constant velocity has a kinetic energy of 2.0  104 J. What is the speedometer reading of the car in km/h?

1. A 1000 kg car is driving forward with a speed of 25 m/s. It comes to rest in a distance of 100m. a) What is its change in kinetic energy during this process? ANSWER: b) What was the magnitude of the net force needed to bring the car to rest over that distance? ANSWER:

3.) A public bus (with mass 2500 kg) is traveling along H1 highway at a speed of 3 m/s. Suddenly the bus- driver jams on the brakes and the bus comes to a complete stop. a) How much kinetic energy does the bus have initially? b) How much kinetic energy does the bus have when it comes to a complete stop? c) If the brakes exert a force of 1000 N, how much braking distance does the car need to come to a complete stop? d) If the car was traveling at double the speed (6 m/s), how much braking distance would be required?

A 13 kg ball is dropped from a height of 14 m?  As it falls, air drag does -50 J of work against the ball.  How much kinetic energy (in joules) does the ball have when it reaches the ground? Use g =9.8 m/s2.

4. The speed of a 1600 kg car increases uniformly from 20 m/s to 30 m/s. (a) What is the increase in its kinetic energy? (b) If the acceleration increases over a distance of 50 m, what force is accelerating the car?