A car is traveling at a velocity of 40km/h and brakes in 5.0 seconds. How much must velocity change each second?
the answer is -2.2m/s
but i want to know how to get that answer.
A car is traveling at a velocity of 40km/h and brakes in 5.0 seconds. How much must velocity change each sec.?
I converted the speed to m/s
40 km/h= about 11m/s
He then comes to a stop in 5 sec.
We will use this information to find acceleration, which will lead to the change in speed per sec.
a= (change in speed)/t
change in speed= -11 m/s
t= 5 sec
a= -11/5, which comes out to be -2.2m/s虏, which is how much he slows down in 1 sec.
A car is traveling at a velocity of 40km/h and brakes in 5.0 seconds. How much must velocity change each sec.?
V = -40/3.6 = -11.11 m/s
11.11m/s/5s = -2.22 m/s虏
well first convert 40 km/h into m/s
40km x 1000m x 1h
-------- --------- ----
1 h 1km 3600s
the km cancel and the hours cancel and u get 11.1 m/s
then divide 11.1m/s by 5s to get how many meters u stop per second and u get 2.2m/s. but then u must make it negative because u are decreasing velocity. if u were increasing it would be positive.
40 km/h to zero in 5 secs
=8 km/h in 1 sec, or 8km/h/sec
Now 8 km = 8000 metres,
so we're talking about 8000 metres/h/sec
= 8000/3600 metres/sec/sec (3600 seconds in an hour)
= 2.22 metres /sec each second.
V=40 km/h = 11.1111111 meters / second
T= 5 s
a=V/T %26quot;and add the - sign!%26quot;
you take it from here
good luck
