When the traffic light turns green, a car accelerates from rest at a rate of 2.0ms-2. At the same time, a truck, moving at a constant speed of 10ms-2, passes the traffic light, which just turns green, and overtakes the car. Since the car moves with increasing speed, it will overtake the truck some times later.
(a) At what distance from the traffic light will the car overtake the truck?
(b) What is the speed of the car at that instant?作者: Ameril 時間: 2010-9-16 01:00 PM
這題跟我前面幫你做的那道free fall是一樣的概念. 而且還比較簡單一點
When the traffic light turns green, a car accelerates from rest at a rate of 2.0ms-2. At the same time, a truck, moving at a constant speed of 10ms-2, passes the traffic light, which just turns green, and overtakes the car. Since the car moves with increasing speed, it will overtake the truck some times later.
(a) At what distance from the traffic light will the car overtake the truck?
truck is running at 10 m/sec and the car is running with 0 initial velocity and 2.0 m/sec acceleration. You can set up two equation and solve it analytically.
truck travel distance = 10m/sec * t
car travel distance = 1/2*2.0m/sec^2 * t^2
solve for t. since the distance that car and truck traveled are the same