Concept #1: Intro to Meet/Catch Problems

Concept #2: Meet/Catch Problems (Practice Intro)

Practice: Two horny teenagers run towards each another. The guy, initially at the bar, runs with 5 m/s. The girl runs from 60 m away from the bar with 4 m/s. How long does it take for them to meet?

Practice: In a race, your friend takes off with 3 m/s^2. You take off 2 seconds later with 4 m/s^2. How far into the race will you catch up to him?

A motorist traveling at a constant velocity of 20 m/s passes a school-crossing corner where the speed limit is 10 m/s (about 22 mi/h). A police officer on a motorcycle stopped at the corner starts off in pursuit with constant acceleration of 2.5 m/s2. What is the officer's speed when she catches up with the car?

A motorist traveling at a constant velocity of 20 m/s passes a school-crossing corner where the speed limit is 10 m/s (about 22 mi/h). A police officer on a motorcycle stopped at the corner starts off in pursuit with constant acceleration of 2.5 m/s2. What is the total distance the officer has traveled at the point he catches the motorist?

A 1/4 mile drag race is going to occur between a Porsche GT3 and a Ferrari F430. The Porsche is the faster car, able to accelerate across a 1/4 mile at about 6.5 m/s2, which the Ferrari can only accelerate across the same stretch at about 5.8 m/s2. At the start of the drag race, though, the driver of the Ferrari gets off the line faster than the Porsche, by about 0.5 s. Is this enough of a head start for the Ferrari to win? Note that 1/4 mile is about 400 m.

A car capable of a constant acceleration of 2.64 m/s2 is stopped at a traffic light. When the light turns green, the car starts from rest with this acceleration. At the very same moment, a truck traveling with constant velocity 17.3 m/s passes the car. As the car’s velocity increases, it will eventually move faster than the truck and later overtake it. How far from the light will the car catch up with the truck?
1. 171.127
2. 43.6985
3. 116.654
4. 131.742
5. 210.032
6. 162.959
7. 259.102
8. 53.2193
9. 226.735
10. 323.646

Two cars, an Acura and a Bentley, are initially at rest a distance L from each other. At time t = 0 both cars starts accelerating toward each other with constant acceleration aA and aB respectively.
a) At what time does the crash happen?
b) Find the distance traveled by the Bentley before the two cars crash into each other.
c) What is the relative speed of the Bentley, with respect to the Acura, just before the crash?
Write your results in terms of L, a A, and aB. Remember to check the dimensions/units for each answer.

Two locomotives approach each other on parallel tracks. Each has a speed of exttip{v}{v} 85 km/h with respect to the ground. If they are initially exttip{L}{L} 7.0 km apart, how long will it be before they reach each other?

A top fuel dragster and a Bugatti Veyron race in a short straight line drag race. At the start of the race the top fuelers is standing still waiting for the Bugatti to show up. The race starts when the Bugatti crosses the starting line at its top speed of 400 km per hour. At that instant, the top fuel driver accelerates to 4.5 gs and continues to do so for the entirety of the race. How long will it take the top fueler catch the Bugatti?

Suppose the elevator starts from rest and maintains a constant upward acceleration of 4.10 m/s2. A bolt in the elevator ceiling 3.10 m above the elevator floor works loose and falls. It falls out the instant the elevator begins to move. (a) How long does it take for the bolt to reach the floor of the elevator? (b) Just as it reaches the floor, how fast is the bolt moving according to an observer in the elevator? (c) According to an observer in the elevator, how far has the bolt traveled between the ceiling and floor of the elevator? (d) Just as it reaches the floor, how fast is the bolt moving according to an observer standing on the floor landings of the building? (e) According to an observer standing on the floor landings of the building, how far has the bolt traveled between the ceiling and floor of the elevator?

An inquisitive physics student and mountain climber climbs a 50.0-m-high cliff that overhangs a calm pool of water. He throws two stones vertically downward, 1.00 s apart, and observes that they cause a single splash. The first stone has an initial speed of 2.00 m/s. (a) How long after release of the first stone do the two stones hit the water? (b) What initial velocity must the second stone have if the two stones are to hit the water simultaneously? (c) What is the speed of each stone at the instant the two stones hit the water?

While driving on the highway at a constant speed v0, significantly above the speed limit, you pass in front of a parked police car without noticing it. After a few seconds, during which time you have moved a distance d, the police car starts chasing you with a constant acceleration a0. Give your answers in terms of v 0, d, and a0. Assuming that you keep moving at a constant speed, and that the highway can be considered straight:[a] How long will it take for the police car to reach you?[b] How far has the police car traveled when it reaches you?[c] What is the speed of the police car when it reaches you?

An unmarked police car traveling a constant 95 km/h is passed by a speeder traveling 135 km/h. Precisely 1.00 s after the speeder passes, the police officer steps on the accelerator; if the police car’s acceleration is 2.00 m/s2, how much time passes before the police car overtakes the speeder (assumed moving at constant speed)?