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1. A motorcycle has a constant acceleration of 2.69 m/s 2 . Both the velocity an

ID: 1655138 • Letter: 1

Question

1. A motorcycle has a constant acceleration of 2.69 m/s2. Both the velocity and acceleration of the motorcycle point in the same direction. How much time is required for the motorcycle to change its speed from (a) 26.2 to 36.2 m/s, and (b) 56.2 to 66.2 m/s?

2. A sprinter explodes out of the starting block with an acceleration of + 2.17 m/s2, which she sustains for 1.28 s. Then, her acceleration drops to zero for the rest of the race. What is her velocity at (a)t = 1.28 s and (b) at the end of the race?

3. Suppose a car is traveling at +18.4 m/s, and the driver sees a traffic light turn red. After 0.325 s has elapsed (the reaction time), the driver applies the brakes, and the car decelerates at 5.00 m/s2. What is the stopping distance of the car, as measured from the point where the driver first notices the red light?

Explanation / Answer

Q.1 t = ( v-u)/ a

a) t = (36.2-26.2) / 2.69 = 3.717 sec apprx

b) t= (66.2-56.2)/ 2.69= 3.717 sec apprx

Q.2 v = u + at

a) v = 0 + 2.17 (1.28) =2.78 m/s apprx

b) v = 2.78 + 0 = 2.78 m/s

Q. 3

we willuse a combination of equations.

s= ut

v^2 = u^2 - 2as

stopping dsiatnc e= 18.4 ( 0.325) + 18.25^2 / ( 2x 5) = 5.98 + 33.306 = 39.286 m apprx