NASAs Langley Research Centre has been experimenting with the use of air bags to soften the landings of crew exploration vehicles (CEV) on land. What stopping time will be required in order to safely stop a 7250kg CEV moving at 7.65 m/s with an average force of 426,000 N (an average force of 6 Gs)? An automobile accident investigator needs to determine the initial westerly velocity of a Jeep (m=1720 kg) that may have been speeding before colliding head-on with a Volkswagen (m=1510 kg) that was moving with a velocity of 75.7 km/h east. The speed limit on this road is 90km/h. After the collision, the Jeep and the Volkswagen stuck together and continued to travel with a velocity of 15.5 km/h west. a. Find the initial westerly velocity of the Jeep. b. Was the Jeep speeding? Eight people are involved in a tug-of-war. The blue team members pull the rope with the forces of 220N, 340N, 180N, and 560N. Three members of the red team pull 250N, 160N, and 420N. With what force must the fourth person pull the rope to maintain equilibrium? A torque wrench reads 25 lb ft. a. If its length is 1.0 ft, what force is being applied to the wrench? b. What is the force if the length is doubled? A 475 kg pre-stressed concrete beam is to be raised 10.0 m in 24.0 s. How many kilowatts of power is needed for the job? A 1250 kg wrecking ball is lifted to a height of 12.7 m above its resting point. When the wrecking ball is released, it swings toward an abandoned building and makes an indentation of 43.7 cm in the wall. a. What is the potential energy of the wrecking ball? b. What is the kinetic energy at the time of striking the wall? c. If the wrecking ball transfers all of its kinetic energy to the wall, how much force does the wrecking ball apply to the wall? d. Why should a wrecking ball strike a wall at the lowest point in its swing?
