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

unbalanced force

explanation:

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.