Adriver enters a one-lane tunnel at 34.4 m/s. the driver then observes a slow-moving van 154 m ahead travelling (in the same direction as the car) at a constant 5.65 m/s. the driver applies the brakes (ignore reaction time)of the car but can only accelerate at -2.00 m/s2 because the road is wet. how fast are you moving when you hit the rear of the van?
(a) 16.3 m/s
(b) 22 m/sec
(с) 4 m/sec
(d) 0 m/s

Ans. B) 22 m/s (the closest to what I have which was 20.16 m/s)

Explanation:

Hi, well, first, we have to find the equations for both, the driver and the van. The first one is moving with constant acceleration (a=-2m/s^2) and the van has no acceletation. Let´s write down both formulas so we can solve this problem.

or by rearanging the drivers equation.

Now that we have this, let´s equal both equations so we can tell the moment in which both cars crashed.

To solve this equation we use the following formulas

Where a=1; b=-28.75; c=154

So we get:

At this point, both answers could seem possible, but let´s find the speed of the driver and see if one of them seems ilogic.

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This means that 21.63s will outcome into a negative speed, for that reason we will not use the value of 21.63s, we use 7.12s and if so, the speed of the driver when he/she hits the van is 20.16m/s, which is closer to answer  A).

Best of luck

speed

ratio of distance traveled to time interval

net force

vector sum of forces on object

object

source of diverging light rays either luminous or illuminated

don't remove my answer im trying my best to answer them

explanation: