Question

A truck is speeding down the highway when it notices a cop on the side of the road. The truck accelerates at -2.0 m/s² for 3.0 seconds, decreasing its speed to 60.0 m/s. How fast was the truck initially traveling?

a) 54.0 m/s

b) 66.0 m/s

c) 60.0 m/s

d) 48.0 m/s

Answer 1

The truck was initially traveling at a speed of 66.0 m/s.

Step-by-step explanation:

The truck initially traveling at a certain speed before it starts accelerating at -2.0 m/s² for 3.0 seconds. We can use the equation for motion with constant acceleration to find the initial velocity of the truck.

1. Use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time.
2. Substitute the given values: v = 60.0 m/s, a = -2.0 m/s², and t = 3.0 seconds.
3. Rearrange the equation to solve for u: u = v - at.
4. Substitute the values into the equation: u = 60.0 m/s - (-2.0 m/s² * 3.0 s).
5. Calculate the expression: u = 66.0 m/s.

Therefore, the truck was initially traveling at a speed of 66.0 m/s.