Chapter 2, Problem 43P

You're an investigator for the National Transportation Safety Board, examining a subway accident in which a train going at 90 km/hkm/h collided with a slower train traveling in the same direction at 24 km/hkm/h . Your job is to determine the relative speed of the collision, to help establish new crash standards. The faster train's "black box" shows that it began negatively accelerating at 2.1 m/s2m/s2 when it was 52 mm from the slower train, while the slower train continued at constant speed. What do you report ?

A red train traveling at 72 km/h and a green train traveling at 144 km/h are headed toward each other on a straight, level track. When they are 950 m apart, each engineer sees the other's train and applies the breaks. The brakes slow each train at the rate of 1.0 m/s^2. Is there a collision? If so, what is the speed of the red train and the speed of the green train? If not, what is the separation between the trains when they stop?

After returning from the bend, a train driver with a speed of 97 km/h recognizes a car 61 m away from the train and moving with a constant speed of 48 km/h. The train driver immediately applies the brake. If the train slows with a constant acceleration, what should be the acceleration in order to avoid from the collision of the train and car?

You are investigating an accident that occurred early on a foggy morning in Oxfordshire. A 2015 Prius Hatchback traveling due north collided in a highway intersection with a 2012 Nissan Pathfinder that was traveling due east. After the collision, the wreckage of the two vehicles was locked together and skidded across the level ground until it struck a tree. You measure that the tree is 11 m from the point of impact. The line from the point of impact to the tree is in a direction 39° north of east. From experience, you estimate that the coefficient of kinetic friction between the ground and the wreckage is 0.45. Shortly before the collision, a police officer with a laser speed gun measured the speed of the Prius to be 80 km/h and, according to a witness, the Prius driver made no attempt to slow down. Four people with a total mass of 230 kg were in the Nissan. The only person in the Prius was the 80 kg driver. The Nissan with its passengers had a mass of 2362 kg, and the Prius with its…

An initially motionless test car is accelerated uniformly to 135 km/hr in 8.08 seconds before striking a simulated deer. The car is in contact with the faux fawn for seconds, after which the car is measured to be traveling at 87.5 km/hr. What is the magnitude of the average acceleration of the car during the collision?

A body moving along the horizontal has an acceleration that is directly proportional to the square of the time, "t" at 0 < t <6 seconds. Initially, the body was at x = 12cm. After 4.3 seconds, the body was at x = 0.636 m and gained a velocity of 9 cm/s. Express "v" (cm/s) in terms of "t", in vector form.

Nerve impulses travel at different speeds, depending on the type of fiber through which they move. In a scenario, the impulses for touch traveled at 57.3 m/s, while those registering for pain moved at 0.82 m/s. If a person stubs his toe, find the time delay between the pain and touch impulses. Assume that his brain is 1.60 m from his toe and that the impulse travels directly from toe to brain. Express your answer in seconds.   Hint: Always take the positive value. Time difference is synonymous to time delay.

A driver in Massachusetts was sent to traffic court  for speeding. The evidence against the driver was that the policewoman observed the driver's car alongside a second car at a certain moment, and the policewoman had already clocked the second car as going faster than the speed limit. the driver argued,"" The second car was passing me. I was not speeding." the judge ruled against the driver because, in the judge's words, "If two cars were side by side, you were both speeding". If you were the lawyer representing the accused driver, how would you argue this case? Explain in 10 sentences

Super Mario is preparing to jump into a pipe. During motion analysis of his awesome pipe jumping abilities, just prior to his jump, he has flexed his knee. Coordinates of his legs were measured. His hip point is at (3,8), his knee is at (9,4), and his ankle is at (7,-1). The coordinates are measured in cm. a) how long is his thigh? b) how long is his shank (lower leg)? c) What is the angle of his knee joint?