Car is driving with a speed of 36km/h. Then the car stops completely in 2 seconds. What is the negative acceleration of the car?
I know that this is a very easy problem but I'd be very happy if someone could write the steps of it.
Thank you
I know that this is a very easy problem but I'd be very happy if someone could write the steps of it.
Thank you
1 Answer
Explanation:
We're asked to find the acceleration of the car, given its initial speed and how long it takes to stop.
To do this, we can use the equation
v_x = v_(0x) + a_xtvx=v0x+axt
where
-
v_xvx is the final velocity of the car -
v_(0x)v0x is the initial velocity of the car -
a_xax is the constant acceleration of the car (what we're trying to find) -
tt is the time
We know:
-
v_(0x) = 36color(white)(l)"km/h"v0x=36lkm/h -
t = 2t=2 "s"s = ul(5.56 xx 10^-4color(white)(l)"h" (units must be consistent) -
and the final velocity
v_x = 0 , because it comes to a stop
Plugging i known values:
0 = 36color(white)(l)"km/h" + a_x(5.56xx10^-4color(white)(l)"h")
color(red)(ulbar(|stackrel(" ")(" "a_x = -6.48xx10^4color(white)(l)"km/h"^2 = -5.00color(white)(l)"m/s"^2" ")|)
The acceleration of the car is thus