# Physics

An engineer in a locomotive sees a car stuck
on the track at a railroad crossing in front of
the train. When the engineer first sees the
car, the locomotive is 210 m from the crossing
and its speed is 26 m/s.
If the engineer’s reaction time is 0.62 s,
what should be the magnitude of the mini-
mum deceleration to avoid an accident?

1. 👍
2. 👎
3. 👁
1. During the engineer's reaction time, the train travels 26 x 0.62 = 16 meters. To avoid a collision after that, the train's speed must be reduced to zero while traveling less than 194 m.

While decelerating, the average speed will be 26/2 = 13 m/s

Maximum stopping time
= (194 m)/(13 m/s) = 14.92 s

Required deceleration rate
= (26 m/s)/14.92s = ____ m/s^2

1. 👍
2. 👎
2. 1.742627346

1. 👍
2. 👎
3. 1.742627346

1. 👍
2. 👎
4. 1.742627346 1.742627346 1.742627346 1.742627346

xd

1. 👍
2. 👎
5. where did 194 come from?

1. 👍
2. 👎
6. The 194 is the 210m subtracted by the 16m.

1. 👍
2. 👎
7. Why does the average speed while decelerating equal 13m/s?

1. 👍
2. 👎

## Similar Questions

1. ### physics

The position of a toy locomotive moving on a straight track along the x-axis is given by the equation x = t4 − 6 t2 + 9 t , where x is in meters and t is in seconds. The net force on the locomotive is equal to zero when t is

2. ### physics

An engineer in a locomotive sees a car stuck on the track at a railroad crossing in front of the train. When the engineer first sees thecar, the locomotive is 310 m from the crossingand its speed is 10 m/s.If the engineerâ€™s

3. ### physics

An engineer in a locomotive sees a car stuck on the track at a railroad crossing in front of the train. When the engineer first sees the car, the locomotive is 330 m from the crossing and its speed is 21 m/s. If the engineer’s

4. ### physics

A certain cable car is San Francisco can stop in 10 s when traveling at maximum speed. On one occasion, the driver sees a dog a distance d m in front of the car and slams on the brakes instantly. The car reaches the dog 7.78 s

1. ### physics

A locomotive is pulling 17 freight cars, each of which is loaded with the same amount of weight. The mass of each freight car (with its load) is 37,000 kg. If the train is accelerating at 0.7 m/s2 on a level track, what is the

2. ### Physics

A train 500 m long is moving on a straight track with a speed of 84.2 km/h. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 16.4 km/h. Assuming constant acceleration,

3. ### Physics

The rolling resistance for steel on steel is quite low; the coefficient of rolling friction is typically μr=0.002. Suppose a 180,000 kg locomotive is rolling at 19 m/s on level rails. A) If the engineer disengages the engine, how

4. ### Physics

When a high-speed passenger train traveling at 161 km/h rounds a bend,the engineer is shocked to see that a locomotive has improperly entered onto the track from a siding and is a distance(D)= 676m ahead.The locomotive is moving

1. ### physics

an engineer in a locomotive sees a car stuck in the track at a railroad crossing in front of the train. when the engineer first sees the car, the locomotive is 160 m from the crossing and its speed is 29m/s. if the engineer’s

2. ### English

Which sentence describes a race car using onomatopoeia? A. The sweet car went around the track quickly. B. The rapid race car drove around the track. C. The fast car traveled around the roadway D. The sleek, powerful race car

3. ### physics

A locomotive pulls a series of wagons. Which is the correct analysis of the situation? A. because action always equals the reaction,the locomotive cannot pull the wagons,-the wagons pull backward just as hard as the locomotive

4. ### Physics

Some how TRAIN A travelling at 36 m/s, is accidentally sidetracked onto the train track for TRAIN A. The TRAIN A engineer spots TRAIN A 100 m ahead on the same track and travelling in the same direction. The engineer jams on the