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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: YellowTongue on June 19, 2015, 02:44:18 pm

Title: Why am I getting this wrong?
Post by: YellowTongue on June 19, 2015, 02:44:18 pm

A bus traveling north along a straight toad at 60km/h slows down uniformly and takes 5.0s to stop.

 Calculate the magnitude of its acceleration in km/h/s

So using the formula for acceleration;

Acceleration=v-u/time takes
                 =0-60/5
                 =-12

However, the book says that the magnitude is +12, not negative. I figured that the answer should be negative, seeing as the bus is slowing down, not speeding up Why is my answer incorrect?
                 

Title: Re: Why am I getting this wrong?
Post by: Kel9901 on June 19, 2015, 03:23:40 pm

Quote from: YellowTongue on June 19, 2015, 02:44:18 pm

A bus traveling north along a straight toad at 60km/h slows down uniformly and takes 5.0s to stop.

 Calculate the magnitude of its acceleration in km/h/s

So using the formula for acceleration;

Acceleration=v-u/time takes
                 =0-60/5
                 =-12

However, the book says that the magnitude is +12, not negative. I figured that the answer should be negative, seeing as the bus is slowing down, not speeding up Why is my answer incorrect?
                 

'magnitude' means just the number/size and not the direction. hence 'magnitude' is always positive (or zero) and 12 is the right answer.