Question

1) The position of a particle moving along x direction is given by: x=8t-3t².What is the velocity of the particle at t=2 s and what is the acceleration?

2) A roller coaster car starts from rest and descends h₁= 40 m. The car has a mass of 75 kg. What is the speed at 20m while going down the hill?

Answer 1

1)

       = 8-6t

velocity at time t= 2s

v = 8-6*2 = -4 m/s

aceeleration a=

                 a = -6 m/s²

2) from the conservation of energy

   mgh₀ = 1/2 mv² + mgh

         v =

           =

           =19.79 m/s