On a lonely highway, with no other cars in sight, you decide to measure the angular acceleration of your engine’s crankshaft while braking gently. Having excellent memory, you are able to read the tachometer every 1.0 s and remember seven values long enough to later write them down. The table shows your data:

Time(s)                                 rpm

    0.0  .................................   3010

    1.0  ..................................  2810

    2.0  ..................................  2450

    3.0  ..................................  2250

    4.0  ..................................  1940

    5.0  ..................................  1810

    6.0  ..................................  1510

What is the magnitude of the crankshaft’s angular acceleration? Give your result in rad/s².