Asports car starts from rest at an intersection and accelerates toward the east on a straight road at 8.0 m/s2. just as the sports car starts to move, a bus traveling east at a constant 18 m/s on the same straight road passes the sports car. when the sports car catches up with and passes the bus, (a) how much time has elapsed and (b) how far has the sports car traveled?

a)  t = 4.5 s , b)    x = 81 m

Explanation:

a) For this problem we will use kinematic relationships

For the car

        x = v₀ t + ½ a₁ t²

Since the car kicks from rest, the initial speed is zero

         x = ½ a₁ t²

For the bus

        v₂ = x / t

       x = v₂ t

At the point where they are located it has the same position, so we can match the equation

       ½ a₁1 t² = v₂ t

       ½ a₁ t = v₂

        t = 2 v₂ / a₁

Let's calculate

       t = 2 18 /8.0

       t = 4.5 s

b) to find the position

        x = v₂ t

        x = 18   4.5

        x = 81 m

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.

option number c is the right answer.