If a car traveling at 60 km/h will skid 20m when its brakes lock, how far will it skid if it traveling at 120 km/h when its brakes lock?

80 m (assuming the car's deceleration is the same)

Explanation:

The distance the car needs to completely stop is given by the following suvat equation:

where

v = 0 is the final velocity of the car

u is the initial velocity of the car

a is the deceleration of the car

d is  how far the car travels

Re-arranging the equation, we have

So, we see that d is proportional to the square of the initial velocity, . Therefore, if in the initial situation the car starts with and travels d=20 m, then if the car travels at twice the initial velocity (, it will cover a distance four times larger, i.e. 80 m.

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.