Question

A toy race car zooms across the ground with an acceleration of 1.8 m/s² . After 3 seconds, it has a final velocity of 12.2m/s. What is the toy car's initial velocity?

A) 5.6m/s
B) 6.8m/s
C) 7.4m/s
D) 8.6m/s

Answer 1

The initial velocity of the toy race car is calculated using the kinematic equation v = u + at. With the given final velocity of 12.2 m/s, acceleration of 1.8 m/s², and time of 3 seconds, the initial velocity is found to be 6.8 m/s. The correct answer is option B.

Step-by-step explanation:

The student is asking how to find the initial velocity of a toy race car knowing its acceleration and final velocity after a certain time interval. The initial velocity can be calculated using the kinematic equation:

v = u + at

where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. Plugging in the known values (v = 12.2 m/s, a = 1.8 m/s², and t = 3 s) and solving for u, we get:

u = v - at

u = 12.2 m/s - (1.8 m/s² × 3 s)

u = 12.2 m/s - 5.4 m/s

u = 6.8 m/s

Therefore, the initial velocity of the toy race car was 6.8 m/s.