MasteringPhysics Assignment& Motion with constant acceleration-Goo 2 Secure http
ID: 1654447 • Letter: M
Question
MasteringPhysics Assignment& Motion with constant acceleration-Goo 2 Secure https://session.masteringphysics.com/myct/itemView? Assignment 5 Motion with constant ac. Item 7 Item 7 A car and a train move together along straight, parallel paths with the same constant cruising speed vo. At t = 0 the car driver notices a red light ahead and slows down with constant acceleration-ao. Just as the car comes to a full stop, the light immediately turns green, and the car then accelerates back to its original speed vo with constant acceleration ao. During the same time interval, the train continues to travel at the constant speed vo |Explanation / Answer
we will use kinematic equations,
a)t = ( V-vo)/ -a0 ( where V is the final speed)
t1= V0/a0
b) v0 = 0 + a0t2
t2= v0/a0
c)distance travelled duting t1+ t2= v0 t1 - 0.5 ( a0) ( t1)^2 + 1/2 a0 (t2)^2
distance travelled by train during t1 +t2 = ( v0 ) (t1+t2)
=( v0 ) (t1+t2) - v0 t1 + 0.5 ( a0) ( t1)^2 - 1/2 a0 (t2)^2= v0 t2 + 0.5 a0 ( t1^2 - t2^2)
=v0t2 + 0.5 a0 (0) = v0t2