Solving Circular Motion: Train Slows from 90 to 50 km/h

[blackboy]

Homework Statement

1. Homework Statement
A train slows down as it rounds a sharp horizontal turn, slowing from
90.0 km/h to 50.0km/h in that 15.0s that it takes to round the bend. The
radius of the curve is 150m. Compute the acceleration at the moment the train
speed reaches 50.0 km/h. Assume that it continues to slow down at this time at
the same rate.

Homework Equations

Kinematics
Circular Motion

The Attempt at a Solution

I understand we have to add the tangential acceleration to the centripetal acceleration. Can I just treat this motion as a straight line to compute the tangential acceleration? Can we do this for most problems like this? If so, then the tangential acceleration is -2.67 m/s^2. Then the total acceleration is 2.96 m/s^2 64.28 degrees of the radius.

 

[rock.freak667]

I assumed you used "90.0 km/h to 50.0km/h in that 15.0s" to get the tangential acceleration of -2.67m/s²?

and then used 50km/h in 150m radius for the normal acceleration right?

then added them up using a vector method?

If so then it should be correct.

 

[blackboy]

Yes, but can we pretend it was 1-d kinematics to find the tangential acceleration?

 

[rock.freak667]

Yes, but can we pretend it was 1-d kinematics to find the tangential acceleration?

that is how you found the tangential acceleration, so yes.