Homework SourseA racing car driver starts from rest at point A and accelera
A racing car driver starts from rest at point A and accelerates uniformly for 10 seconds until she reaches a point B, a distance of 1200ft.
A) What is the magnitude of her acceleration just before she reaches point B?
B) What is the magnitude of her velocity just before she reaches point B?
C) How far has the racing car driver traveled after 5 seconds?
D) At what time does she reach a distance 600ft to the right of A?
E) What is the magnitude of her acceleration just after she passes point B?
Problem 3. Particle Kinematics (38 points). A racing car driver starts from rest at point A and accelerates uniformly for 10 seconds until she reaches point B, a distance of 1200 ft. Curved Track 1200 ft R = 400 ft Figure 3 Solution
a) s=1200ft, t=10s,initial velocity u=0
=>s=u*t+0.5*a*t^2
=>a =s/(0.5*t^2) =1200/(0.5*10^2) =24ft/s^2
b) v=u+a*t =>v=0+24*10 =240ft/s
c) s=u*t+0.5*a*t^2 =0+0.5*24*5^2 =300ft
d) s=0+0.5*a*t^2 =>t =sqrt(2*s/a) =sqrt(2*600/24)=7.071s
e) aB=magnitude of her acceleration just after she passes point B
aB^2 =(v^2/r)^2+a^2 =(240)^2/400+24^2 =720 =>aB=26.83ft/s^2
