Alex, who has a mass of 100kg, is skateboarding at 9.0m/s when he smacks into a brick wall and comes to a dead stop in 0.2 s. show that his deceleration is 45 m/s2. show that the force of impact is 4500n

Given:

m (mass of Alex) = 100Kg

u (initial velocity) = 9 m/s

t (time of impact) = 0.2 s

v (final velocity) = 0.

Now we know that

v=u+at

We know that v is the final velocity.

u is the initial velocity

a is the acceleration

t is the time of impact

Now substituting these values we get

0=9+ax0.2

-0.2a=9

a=-45m/s^2

Thus the acceleration acting on the body is - 45m/s^2

Also we know that

F=mxa

Where F is the force acting on the object.

m is the mass of the object.

a acceleration acting on the object.

F=-100x45

F=-4500 N

Thus the force of impact is - 4500N