Question

driver of a car moving at 30m/s , suddenly he sees a truck i.e. moving in the same direction at 10m/s and is 60m ahead . the maximum deaccaleration of the truck is 5m/s square . 1) will the collision occur , the driver reaction time is zero . 2) if the driver reaction time is .5 seconds is included . what is the minimum magnitude of deaccelaration to avoid the collision

Answer 1

Answer:

Explanation:

truck  moving at 10 m/s

deceleration of the truck is 5m/s²

Distance Covered = (0² - 10²)/(2*5)

=10 m

Truck is 60 + 10 = 70 m Ahead

Distance Covered by Car

= (0² - 30²)/2*5

= 90 m

Hence collision will occur

To avoid collision

30²/2a < 70

=> a > 6.43 m/s²

minimum magnitude of deceleration  = 6.43 m/s²

if reaction time =  0.5 sec

then Distance covered in 0.5 sec = 30 * 0.5 = 15 m

remaining distance = 70 - 15 = 55 m

To avoid collision

30²/2a < 55

=> a > 8.2

minimum magnitude of deceleration = 8.2 m/s

Answer 2

its the correct answer a<4.