Answer:
a) During the reaction time, the car travels 21 m
b) After applying the brake, the car travels 48 m before coming to stop
Explanation:
The equation for the position of a straight movement with variable speed is as follows:
x = x0 + v0 t + 1/2 a t²
where
x: position at time t
v0: initial speed
a: acceleration
t: time
When the speed is constant (as before applying the brake), the equation would be:
x = x0 + v t
a)Before applying the brake, the car travels at constant speed. In 0.80 s the car will travel:
x = 0m + 26 m/s * 0.80 s = <u>21 m </u>
b) After applying the brake, the car has an acceleration of -7.0 m/s². Using the equation for velocity, we can calculate how much time it takes the car to stop (v = 0):
v = v0 + a* t
0 = 26 m/s + (-7.0 m/s²) * t
-26 m/s / - 7.0 m/s² = t
t = 3.7 s
With this time, we can calculate how far the car traveled during the deacceleration.
x = x0 +v0 t + 1/2 a t²
x = 0m + 26 m/s * 3.7 s - 1/2 * 7.0m/s² * (3.7 s)² = <u>48 m</u>
To do this you want to solve for one variable at a time. So we want to cancel out a variable. Lets cancel x. I will multiply the first equation by the number 4 to get 4y=4x-16.
Now lets solve equation 2 for y, giving
-3y=-4x+3 now add equation 1 to equation 2
Y =-13
Now plug that back in to either
-13=x-4
X=-9
So the answer is (-9,-13)
21m per second. Take 210 divided by 10. Hope this helps!
The answer is D. centripetal force
This definition of centripetal force is a force acting towards the center of an object moving in a circular motion. Acceleration is the rate of which velocity changes over a period of time. If you pick a point on say a rotating circle and find the tangential velocity at each point it goes through, the acceleration would be towards the middle.
