Question

Write or type work and solutions on a separate paper, If written, write legibly, 1. The velocity of a car decreases from 30 m/s to 18 m/s in a time of 1 minute. What is the average acceleration of the car in this process? 2. A runner traveling with an initial velocity of 2.00 m/s and accelerates at a constant rate of 1.20 m/s for a time of 10 seconds. a. What is his velocity at the end of this time? b. What distance does the runner cover during this process 3. A car traveling at a constant velocity of 40.2 km/hr for 20 minutes; and then, it deccelarates at a constant rate of 10 km/hr2 a. How long does it take for the car to stop? b. What is the total distance covered by the car when it stops? 4. Extra Credit: If a particle is moving in a line with a velocity function of v(t) 2(t 3) +t+1 m/s 37 what is the instantaneous acceleration of the particle at t -1 and t

answer number three please

Answer 1

From v = u + at 0 = 40.2 - 10 times t t = 4.02 hr Time taken for car to stop t = 241.2 min distance covered in first 20 min S_1 = V times t = 40.2 times 20/60 = 13.4 km distance covered before stop V^2 - u^2 = 2 as 0^2 - (40.2)^2 = -2 times 10 times S_2 S_2 = 80.802 km Total distance covered = S_1 + S_2 = 13.4 + 80.802 S = 94.202 km