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_xt#
where

#v_x# is the final velocity of the car 
#v_(0x)# is the initial velocity of the car 
#a_x# is the constant acceleration of the car (what we're trying to find) 
#t# is the time
We know:

#v_(0x) = 36color(white)(l)"km/h"# 
#t = 2# #"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