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

the diagram which shows forces as either balanced = same speed or unbalanced = accelerarting

true tan speed = ang vel x radius