A 1,200-kilogram car traveling at 10 meters per sec- ond hits a tree and is brought to rest in 0.10 second.
What is the magnitude of the average force acting
on the car to bring it to rest?
1. 1.2 x 102N
2. 1.2 x 103 N
3. 1.2 x 104 N
4. 1.2 x 105N

Ablock of mass m slides on a horizontal frictionless table with an initial speed v0 . it then compresses a spring of force constant k and is brought to rest. the acceleration of gravity is 9.8 m/s2. how much is the spring compressed x from its natural length? 1) x = v0*sqrt(k/(mg)) 2) x=v0*sqrt(m/k) 3) x=v0*((mk)/g) 4) x=v0*sqrt(k/m) 5) x=v0*(m/kg) 6) x=v0*sqrt((mg)/k) 7) x=(v0)^2/(2g) 8) x=v0*(k/(mg)) 9) x=(v0)^2/(2m) 10) x=v0*((mg)/k)