Question

A truck is driving along the highway behind a tractor when it pulls out to pass. If the truck's acceleration is uniform at 2.3 m/s² for 3.2 s and it reaches a speed of 31 m/s, what was its speed when it first pulled out to pass the tractor? 1) 45 m/s 2) 38 m/s 3) 31 m/s 4) 24 m/s 5) 17 m/s

Answer 1

To solve this problem, we can use the kinematic equation:

v = u + at

Where:
v = final velocity (31 m/s)
u = initial velocity (the speed when it first pulled out to pass the tractor)
a = acceleration (2.3 m/s²)
t = time (3.2 s)

We are looking for the initial velocity (u), so we can rearrange the equation:

u = v - at

Substituting the given values:

u = 31 m/s - (2.3 m/s²)(3.2 s)
u = 31 m/s - 7.36 m/s
u = 23.64 m/s

Therefore, the speed of the truck when it first pulled out to pass the tractor was approximately 23.64 m/s.

None of the provided answer options matches this result exactly, but option 4) 24 m/s is the closest approximation.