A bus driver forgot to stop at a bus stop. Just as he passes the stop, he begins to decelerate 5 seconds later, the bus is 80m beyond the stop and has slowed to 10m/s.
a. Calculate the speed of the bus as it passed the bus stop.
b. What is the deceleration of the bus?
Solution;
when a body moves along a straight line with constant acceleration or deceleration,the equations of motion that describe the body's motion are:
......(1)
Where ;
a is acceleration or deceleration.
vf is the final velocity.
v0 is the initial velocity.
t is the time taken.
The displacement in one direction would be;
.....(2)
By substituting (1) into (2),Resolve to;
......(3)
Given;
a)
Calculate speed of bus as it passed the stop; ;
Using equation (3),by direct substitution;
Ans; 22m/s
(b)
Deceleration of the bus;
Using equation (1),by direct substitution;
(Negative shows the bus is decelerating)
Ans;2.4m/s2
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