Atrain starts at rest, accelerates with constant acceleration a for 5 minutes, then travels at constant speed for another 5 minutes, and then decelerates with –a. suppose it travels a distance of 10km in all. find a.

The value of acceleration equals

Explanation:

The  distances covered in each of the three phases are calculated as under

1) Distance covered in accelerating phase for a period of 5 minutes or 300 seconds ( 1 minute = 60 seconds)

Using second equation of kinematics

2) Distance covered in 5 minutes while travelling at a constant speed which is The speed after 5 minutes of travel is obtained by first equation of kinematics as

Thus distance traveled equals

3)

The phase when the car stops the distance it covers during this phase can be obtained using third equation of kinematics as

Now the sum of equals 10 kilometers or 10000 meters.

Thus we get

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table

force tends to be low and long diustance masses are high