Physics Help! 10 Points!!!!?
1) An electric vehicle starts from rest and accelerates at a rate of 2.0 m/s2 in a straight line until it reaches a speed of 16 m/s. The vehicle then slows at a constant rate of 1.2 m/s2 until it stops. (a) How much time elapses from start to stop? (b) How far does the vehicle move from start to stop?
I got part a correct, which is 21.33 seconds, but am confused on b.
2) A certain elevator cab has a total run of 191 m and a maximum speed is 312 m/min, and it accelerates from rest and then back to rest at 1.15 m/s2. (a) How far does the cab move while accelerating to full speed from rest? (b) How long does it take to make the nonstop 191 m run, starting and ending at rest?
3) A car traveling 59.2 km/h is 21.9 m from a barrier when the driver slams on the brakes. The car hits the barrier 2.31 s later. (a) What is the car's constant deceleration magnitude before impact? (b) How fast is the car traveling at impact?