# Physics

posted by on .

an adult 68 kg cheetah can accelerate from rest to 20.1 m/s (45 mph) in 2.0 s. Assuming constant acceleration, (a) find the net external force causing this acceleration. (b) where does the force come from? that is, what exerts the force on the cheetah?

• Physics - ,

a= deltav/time

F=ma

Doesn't the ground exert force on the cheta?

• Physics - ,

i don't get the first equation explain more please

• Physics - ,

acceleration= changeinvelocity/time.

• Physics - ,

should i be using the equation you wrote for finding the net EXTERNAL force??

• Physics - ,

Yes. That is the force accelerating the cheeta.

• Physics - ,

i got 1366.8 N and i'm asked to round to SF would it be 1.3*10^2?

• Physics - ,

a= 20.1m/s /2= 10.05m/s^2
F= ma

How did you get that number 1366?

Now, rounding 1366.8 is not 1/3E2

E2 is 100. But you have other errors that need to be corrected.

• Physics - ,

i corrected it and i got 683.4 N, does that sounds right? if yes, would it be 6.8E-1?