Question

PLEASE solve Practice it a) b) AND exercise a) b) THANKS

PRACTICE IT Use the worked example above to help you solve this problem. A car traveling at a constant speed of 28.6 m/s passes a trooper hidden behind a billboard, as in the figure. One second after the speeding car passes the billboard, the trooper sets off In chase with a constant acceleration of 3.54 m/s2 (a) How long does it take the trooper to overtake the speeding car? Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. s (b) How fast is the trooper going at that time? Your response differs from the correct answer by more than i0%. Double check your calculations. m/s EXERCISE HINTS: GETTING STARTED I P'M STUCK A motorist with an expired license tag travels at a constant speed of 10.7 m/s down a street, and , policeman on a motorcycle, taking another 4.1 s to finish his donut, gives chase at an accelerationof 2.87 (a) Find the time required to catch the car Your response differs from the correct answer by more than 10%. Double check your calculations. (b) Find the distance the trooper travels while overtaking the motorist. Your response differs from the correct answer by more than 10%. Double check your calculations. Need Help?Read It 0

Answer 1

Practice it:

Let t represent the time when the car passes the trooper. The troop starts to accelerate 1 second later. t - 1 is the time at which the troop stars to accelerate

the motion of the car is constant

Xf = vt

Xf = 28.6t

the motion of the troop is accelerating

Xf = .5at^2 + Vt + Xi

Xf = .5(3.54)t^2 + 0t + 0

Xf = 1.77t^2

when the trooper catches the car, they are in a same position

Trooper = car

1.77t^2 = 28.6t

1.77t^2 – 28.6t = 0

t (1.77t – 28.6) = 0

t = 0 or 16.16s

recall that the trooper starts to accelerate 1 second later. So 16.16 - 1 = 15.16 s is the take it takes the trooper to catch the car

b) Vf = at + Vi

Vf = 3.54 * 15.16 + 0

Vf = 53.66 m/s