Respuesta :
Answer:
The initial speed of the car was 80 ft/s.
Step-by-step explanation:
The deceleration is the rate at which the car speed decreases. In this case the speed of the car goes all the way down to 0 ft/s and in order to do that it travelled 50 ft. So we will call the initial speed at which the car started to brake "v_0" and use Torricelli's equation to find it. The equation is given by:
v^2 = (v_0)^2 + 2*a*S
Where v is the final speed, v_0 is the initial speed, a is the rate of acceleration and S is the space travelled. Using the values that the problem gave to us we have:
0^2 = (v_0)^2 - 2*64*50
0 = (v_0)^2 - 6400
(v_0)^2 = 6400
v_0 = sqrt(6400) = 80 ft/s
Notice that in this case "a" was negative, since the car was decelerating instead of accelerating.
The initial speed of the car was 80 ft/s.
Answer:
The inicial speed of the car was 80 feet per hour.
Step-by-step explanation:
To solve this problem, we can use Torricelli formula to calculate the inicial speed of the car:
V2 = Vo2 + 2*a*D
where V is the final speed, Vo is the inicial speed, a is the acceleration and D is the total distance travelled.
Using V=0, a=-64 and D=50, we have:
0 = Vo2 + 2*(-64)*50
Vo2 = 2*64*50 = 6400
Vo = 80 ft/s
The inicial speed of the car was 80 feet per hour.
